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As the shallow coal seams are gradually being exhausted, mining of the lower group of coal seams in the shallowly buried proximity coal seam group becomes inevitable. Due to geological conditions affecting the upper group coal seams, various coal mining methods have resulted in a significant number of non-sufficient and sufficient collapse mining areas. The presence of water and gas in these mining areas can potentially impact the safe production of the lower group coal seams through inter-layer rock fractures. Therefore, studying the evolution characteristics and formation mechanism of inter-layer rock fractures is of utmost importance. In this paper, we employ theoretical analysis, numerical simulation, and similar simulation methods to investigate the evolution characteristics and formation mechanism of inter-layer rock fractures during the mining of the lower 3–1 coal seam. We specifically focus on the formation of different mining areas in the upper 2–2 coal seam, using the mining of 2–2 and 3–1 coal seams in the Hanjiawan coal mine as our research context. The study results reveal that the inter-layer rock fractures exhibit an overall positive trapezoidal distribution in different mining areas. We quantify the variation in density and width of inter-layer rock fractures in the two mining areas by utilizing the concept of rock damage degree. We analyze the overall damage degree, tensile damage degree, and shear damage degree ratios. The formation of inter-layer rock fractures is primarily influenced by the combined effect of various coal mining methods in both the upper and lower coal seams. The stress changes resulting from mining activities in these seams contribute to the development of transverse separation fractures and longitudinal breaking fractures within the inter-layer rock. The stress changes induced by mining operations in the upper and lower coal seams have been analyzed, and distinct stress regions have been identified. To understand the mechanism of inter-layered rock fracture development in the upper and lower coal seams, a mechanical expansion model of inter-layer rock fractures has been constructed for different stress regions. Highlights: The evolution process and development characteristics of inter-layered rock fractures, as well as their differences when different coal mining methods are employed in the upper coal seam, have been revealed. To determine the influencing factors and development patterns of inter-layered rock fractures under different coal mining methods. Quantitatively comparing and analyzing the damage of inter-layered rock and the percentage of damage degree under different coal mining methods, we found that the damage degree was 61% and 52%, respectively. The study shows that when mining the upper coal seam, the inter-layer rock primarily extends through primary microscopic fractures. On the other hand, when opening the lower coal seam, the main development is observed in macroscopic tension fractures and shear misalignment fractures. Based on the study of the development process of macroscopic fractures and microscopic fractures in the inter-layered rock, the mechanism of fracture development and evolution of the inter-layered rock under different coal mining methods has been determined. [ABSTRACT FROM AUTHOR]

To achieve accurate deformation prediction and assess the temporal stability of surrounding rock in underground mines, this study utilizes the G-P algorithm to determine the optimal embedding dimension and time delay for the reconstructed phase space of the deformation time series. Analyzing the dynamic evolution of the nearest phase point and employing grey prediction theory in the phase space reconstruction, we predict the time series of surrounding rock deformation. Results indicate that the optimal embedding dimension and time delay for the deformation time series are 3. The larger the average distance of the nearest phase point, the more pronounced the chaotic characteristics of perimeter rock deformation, signifying a complex intrinsic dynamical system. The grey theory proves effective in short-term, accurate deformation prediction for perimeter rock. Additionally, the identified stability of perimeter rock based on neighboring phase points and deformation prediction results offers a novel approach for evaluating surrounding rock stability in underground mining processes. [ABSTRACT FROM AUTHOR]

Mine tailings are the discarded materials resulting from mining processes after minerals have been extracted. They consist of leftover mineral fragments, excavated land masses, and disrupted ecosystems. The uncontrolled handling or discharge of tailings from abandoned mine lands (AMLs) poses a threat to the surrounding environment. Numerous untreated mine tailings have been abandoned globally, necessitating immediate reclamation and restoration efforts. The limited feasibility of conventional reclamation methods, such as cost and acceptability, presents challenges in reclaiming tailings around AMLs. This study focuses on phytorestoration as a sustainable method for treating mine tailings. Phytorestoration utilizes existing native plants on the mine sites while applying advanced principles of environmental biotechnology. These approaches can remediate toxic elements and simultaneously improve soil quality. The current study provides a global overview of phytorestoration methods, emphasizing the specifics of mine tailings and the research on native plant species to enhance restoration ecosystem services. [ABSTRACT FROM AUTHOR]

A considerable number of coal mines employed room and pillar mining in the last century in northern China, where the goaf remained stable for a period of time; however, with the increased exposure of coal pillars, their collapse may gradually increase. The stability assessment of these old rooms and pillar goafs is challenging due to their concealment, irregular mining patterns, and the long passage of time. The methodology developed in this study, based on "space-sky-earth" remote sensing such as InSAR to trace historical deformation, the UAV observation of current surface damage, and comparison of mining spaces, can rapidly detect on a large scale the collapse of old goafs and the trend of damage. This study is conducted with an example of a coal mine in Yulin, Northern China, where obtained quantitative surface deformation values were integrated with qualitative surface damage interpretation results, followed by a yearly analysis of the overlying rock movement in accordance with the underground coal mining process. The results show that from 2007 to 2021, corresponding surface deformation and damage occurred following mining progress. However, the room and pillar goaf areas had not undergone any surface deformation, nor had there been incidents of landslides or ground fissures; therefore, it was speculated that no roof collapse had occurred in this region. The surface deformation and damage associated with underground coal mining are complex and influenced by the coal seam occurrence, mining methods, strata lithology, terrain slope, temporal evolution, and anthropogenic modifications. These phenomena are representative of the coal mining area, and this methodology can provide a reference for similar endeavors. [ABSTRACT FROM AUTHOR]

The occurrence of potentially toxic elements (PTEs), including twelve heavy metal(loid)s (Cd, Cr, Cu, Ni, Pb, Zn, Hg, As, Co, V, Fe, Mn), fluoride (F−), and nitrate (NO3−) was evaluated in groundwater in the copper mining and smelter area of Bor city (south Carpathian, eastern Serbia). Groundwater samples were analyzed to determine the extent of pollution, identify natural and anthropogenic input of PTEs, and estimate potential human health risks due to exposure to these substances. The results revealed that the groundwater in the study area was highly contaminated with PTEs, particularly Cu and Zn. Multivariate analysis supported the natural and anthropogenic origin of PTEs, with Fe, Mn, and F− classified as naturally occurring, NO3− resulting from agricultural activities, while other PTEs were linked to smelter/mining processes. Geospatial mapping discovered several hotspots with potential high non-cancer and cancer risks to humans through ingestion pathway. From the studied PTEs, As is the most health risk contributing toxic element. The source-specific probabilistic risk assessment indicated the most significant contribution to the hazard index and total cancer risk from accidental leakage of metallurgical wastewater and wastewater from open mine pits. Monte Carlo analysis identified the human body weight and the ingestion rate as the most sensitive risk parameters. The study underscores the need for stringent environmental management measures, emphasizing the critical role of source-specific risk assessments in mitigating potential hazards associated with metallurgical wastewater and open mine pits. [ABSTRACT FROM AUTHOR]

The growing demand for primary mineral resources and the finite nature of mineral reserves necessitate their efficient utilization while minimizing losses. To extend mine life and increase economic reserves, transitioning from open-pit to underground mining has proven to be a viable strategy. Identifying this critical transition depth is pivotal, as it significantly impacts mining profitability. Therefore, in this paper we propose a method to determine the open-pit/underground transition depth based on an economic block model, accounting for the final pit limit and considering the inherent uncertainty in mineral prices. To achieve our research aim, a hypothetical grade model was constructed initially, and we used @Risk software to perform Monte Carlo simulation of copper prices based on historical data. By generating 200 different mineral price scenarios, we created 200 economic block models. Subsequently, nine mining sequences were designed, and seven distinct scenarios were established to ascertain the final open-pit limit and the depth of the transition point between mining methods, contingent on fluctuating mineral prices. Based on the outcomes derived from the seven scenarios, the depth at which the mining method transition from open-pit to underground is recommended to be 375 m from the surface, under the aforementioned uncertainties. This recommendation is based on the cumulative net present value of open-pit/underground mining, as illustrated in scenario number 7. Our findings provide valuable insights for mining companies seeking to optimize resource utilization and maximize profitability while navigating uncertain mineral price environments. [ABSTRACT FROM AUTHOR]

Phytomining (PM) is defined as the process of using plants capable of bio-extracting metals from soil in order to explore them economically. This relatively new, innovative method has been gathering significant attention in both the academic and commercial domains. Conventional mining methods are often economically unviable when applied to lean ores, and they can lead to secondary pollution in soil—a situation that applies to all excavated metals. On the other hand, PM is an environmentally friendly and economically viable solution that addresses the growing demands for metal resources, while simultaneously contributing to energy production by harnessing biomass energy. This comprehensive review presents the current PM techniques, challenges, and the hyperaccumulator plant species that may be used for the extraction of the main targeted elements in the process. Typically, the targeted metals are those of economic value, which can later be deposited or sold to various industries. This review also analyzes the factors influencing the economic viability of PM and proposes potential enhancements. Undeniably, PM offers the opportunity for economically sustainable exploration of metal-rich soils, but its full commercial viability remains constrained under current conditions as scientists are actively searching for the identification and utilization of new hyperaccumulator plant species in different locations worldwide, while creating new relationships and business avenues within the mining industry. Overall, this review highlights the current status of PM technology and the plants used, emphasizing the need for further research to enhance its commercial implementation and its potential to assist the mining industry. We conclude that PM, although a relatively new and unexplored concept, may provide economic and environmental benefits to soil end-users and managers who must cultivate on metal-contaminated soils as PM may turn yield shortages (of specific commercial crops) to benefits if high-yield hyperaccumulators are cultivated for industrial valorization of their high metal-content biomass. [ABSTRACT FROM AUTHOR]

The work presents a history of the exploitation and processing of alluvial gold in Antiquity by the first civilizations of mankind. But those who developed and perfected this technology were the Romans, in Hispania and Britannia, where they mined gold both outcrops and underground. The technology they used was so advanced that it remained unchanged for more than a millennium. [ABSTRACT FROM AUTHOR]

Traditional coal mining processes have increasingly raised concerns about roadways and surface damage. An innovative mining method, based on DSRC technology, has been proposed to address these issues. The DSRC technology involves using bilateral energy gathering devices to achieve roof cutting on both sides of the working face. The N00 method builds upon DSRC technology by incorporating additional auxiliary techniques to achieve roadways and surface protection during mining. With this method, mining N working faces can be accomplished with the advancement of 0 roadway and the retention of 0 coal pillar. The protection mechanism of the DSRC method on roadways and surface is analyzed through theoretical calculation, numerical simulation, and field engineering analysis. The N00 method with DSRC modifies the structure of the roadway roof by changing the long cantilever beam to a short cantilever beam. This modification reduces the stress on the roof and improves the stability of the roadway roof. The DSRC cuts off the stress transmission in a part of the roadway roof, reducing stress concentration on the coal side and enhancing its stability. The N00 method with DSRC increases the amount of strata bulking, utilizing bulking gangue to support the overlying strata, reducing the development height of the plastic zone in the gob, protecting the overlying aquifers, and mitigating damage to the surface ecological environment. Field monitoring results show that the N00 method with DSRC reduces the door-like support stress, NPR anchor cable stress, and deformation of the roadway, decreases stress concentration on the coal side, minimizes surface deformation, and reduces water inflow into the working face. Therefore, the purpose of protecting roadways and the surface is achieved. Highlights: Double-sided roof cutting technique has been proposed to protect roadways and the surface strata. Roadways are protected by altering the structure of the roof and cutting off part of the stress transmission. Surface strata are protected by increasing the amount of strata bulking. [ABSTRACT FROM AUTHOR]

Cut patio construction was a critical process in the medium-deep hole or deep hole mining methods, which mainly included staged blasting or one-time grooved blasting. Cut patio was essential in the medium-deep hole mining technology. The common method, the conventional raising, cage raising and climber raising method was usually used to construct the cutting patio, which has great safety risks and low excavation efficiency, which seriously affects the mine production. In recent years, Sanshandao Gold Mine has researched downward sublevel filling mining with medium and deep hole blasting. This research was currently facing the problem of cut patio construction under the backfill roof. This study demonstrated a one-time grooved blasting method fitting the backfill roof condition and its application. By comparing the characteristics of the straight-hole cutting method and the blasting crater method, the straight-hole cutting method was selected for the cut patio construction. By calculating blasting parameters, the diameter of the charging hole was Φ65 mm, and the diameter of the compensation hole was Φ110mm. The distance between the charging and empty holes was 0.3m, which could meet the requirements of blasting compensation space and free surface. In consideration of the surrounding rock stability conditions, a nine-hole cutout method was selected, containing 29 holes, where the cutout hole was designed with 1 central charging hole, 12 empty holes as compensation holes, 4 auxiliary holes, and 12 peripheral holes, after determining the blast hole plugging length, explosive selection, charge structure, differential time, detonation sequence and other process parameters, an in-situ industrial test of cut patio construction was carried out. The industrial test showed that the one-time grooved blasting plan for patio construction was feasible. The blasting rock particle size is uniform with no large blocks and excessive powder, the blasting disturbance is minor, and the blasting patio dimensions meet the design requirements. Overall, this test provided experiences and a reference basis for other one-time grooved blasting technical applications with similar conditions. [ABSTRACT FROM AUTHOR]

The sustainable development of mining processes requires a deep knowledge of the effectiveness of mining equipment and is quite complex to analyze due to the intrinsic characteristics of the mining industry. In this regard, its measurement and control can lead to appropriate management, improving the mining processes' efficiency, increasing safety levels, and reducing environmental impacts. This paper developed a new methodology to study the effectiveness of equipment in mining processes, researching the impacts of process management, process control, operating conditions, operational mining schedule, and maintenance programs on the effectiveness of drilling rig fleets using two actual coal mines located in the northwest of Spain and data collected over 10 years. Thus, a new method, called Overall Mining Equipment Effectiveness (OMEE), was developed, verifying its appropriateness and flexibility to analyze the effectiveness of mining equipment by examining the availability rate, utilization rate, and productivity index. [ABSTRACT FROM AUTHOR]

This study uses a data-driven approach to mine the distribution of personality traits among Chinese people in the Chinese social context. Based on the hypothesis of personality lexicology, word embedding technology was employed in machine learning to mine personality vocabulary from Tencent's word embedding database. More than 10,000 Chinese personality descriptors were extracted and analyzed using Gaussian Mixture Model Cluster and Hierarchical clustering analysis. The data was collected from 658 Chinese people randomly from all parts of China through an online questionnaire method. The results reveal six personality traits in the Chinese context, expanding the personality thesaurus and providing examples to illustrate each trait. The findings coincide with previous research on the five-factor model, which partially describes the personality traits of Chinese people, but does not offer a complete explanation of their typical social behavior patterns. Additionally, the study supports the notion of cultural particularity in personality traits. The approach used in this study offers a richer personality vocabulary than traditional personality mining methods, and word embedding technology captures richer semantic information in Chinese. The six Chinese personality traits identified in this study will also be used to explore how to quantify and evaluate personality traits based on word embedding and personality descriptors. [ABSTRACT FROM AUTHOR]

In order to identify and evaluate reservoir wettability, so as to select suitable mining methods to improve oil recovery, wettability evaluation through one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) technology combined with physical simulation experiments was carried out in this study, and the feasibility of the experimental method was verified by contact Angle method. According to the principle of hydrophilic inorganic content and hydrophobic organic content of shale, the wettability can be evaluated through vacuum self-imbibition oil and self-imbibition water physical simulation experiments combined with 1D NMR technology, that is, total water absorption can be considered as inorganic content, organic content can be obtained by subtracting total water absorption from total oil absorption, and adsorbed oil content can be obtained by subtracting pore volume from total oil absorption. In addition to the wettability measurement by contact Angle method to verify the experimental method, the occurrence ratio of adsorbed oil can also be verified twice by 2D NMR spectrum. The results show that the error between the proportion of adsorbed oil measured by 2D NMR spectrum and that measured by self-imbibition method is within 4%. In the saturated oil-bound water state, the bound water is within the relaxation interval of 11<10 ms and 12<10 ms, and the oil signal is within the relaxation interval of T1>10 ms and T2>10 ms. And the relaxation time of aqueous phase moved to the right compared with that in the saturated water state, the interaction force between water and the pore wall was weakened, showing the characteristics of free fluid, and the rock sample became oil-wet, which was consistent with the wettability results measured by contact Angle. Therefore, the wettability of rock samples can be evaluated by 1D NMR technique combined with vacuum imbibition method, or by analyzing the changes of NMR spectra of aqueous phase in completely saturated water and saturated oil-bound water. [ABSTRACT FROM AUTHOR]

Software security analysts typically only have access to the executable program and cannot directly access the source code of the program. This poses significant challenges to security analysis. While it is crucial to identify vulnerabilities in such non-source code programs, there exists a limited set of generalized tools due to the low versatility of current vulnerability mining methods. However, these tools suffer from some shortcomings. In terms of targeted fuzzing, the path searching for target points is not streamlined enough, and the completely random testing leads to an excessively large search space. Additionally, when it comes to code similarity analysis, there are issues with incomplete code feature extraction, which may result in information loss. In this paper, we propose a cross-platform and cross-architecture approach to exploit vulnerabilities using neural network obfuscation techniques. By leveraging the Angr framework, a deobfuscation technique is introduced, along with the adoption of a VEX-IR-based intermediate language conversionmethod. This combination allows for the unified handling of binary programs across various architectures, compilers, and compilation options. Subsequently, binary programs are processed to extract multi-level spatial features using a combination of a skip-gram model with self-attention mechanismand a bidirectional Long Short-TermMemory (LSTM) network. Finally, the graph embedding network is utilized to evaluate the similarity of program functionalities. Based on these similarity scores, a target function is determined, and symbolic execution is applied to solve the target function. The solved content serves as the initial seed for targeted fuzzing. The binary program is processed by using the de-obfuscation technique and intermediate language transformation method, and then the similarity of program functions is evaluated by using a graph embedding network, and symbolic execution is performed based on these similarity scores. This approach facilitates cross-architecture analysis of executable programs without their source codes and concurrently reduces the risk of symbolic execution path explosion. [ABSTRACT FROM AUTHOR]

Much dust is generated in underground coal mining processes, posing threats to workers' health and safety production. Dust enters the human body mainly through inhalation, primarily determined by the dust concentration around workers. In this study, the airflow field and dust distribution in the tunnel are simulated with FLUENT software. The breathing zone for a worker was defined to clarify the extent of external dust distribution influencing dust inhalation. The effects of human respiration, dust production rates, air supply velocities, and workers' positions on dust concentration in the breathing zone were investigated. The results show that there is upward airflow around the worker standing in the center of the air circulation. Human breath barely influences the airflow distribution and respirable dust concentrations in the breathing zone. Reducing the dust production rate in the tunnel can decrease the respirable dust concentration in the breathing zone by almost the same proportion. While increasing the air supply velocity by 50% would reduce only 20% of dust in the breathing zone. The dust concentrations vary along the roadway, in which the low concentration zone is located in the middle, more than 1.0 m away from the dust-producing surface and the wind surface. The research contributes to reducing workers' dust exposure with suggestions regarding ventilation optimization and working position selection. [ABSTRACT FROM AUTHOR]

The behaviour of a stratified backfilled stope in terms of strength development and stress distribution has not been well established in the field of rock engineering. Yet, the mining industries with massive ore bodies are looking into high production with a high standard of safety which is mainly governed by large excavation with backfill as a support system. It is difficult to fill these large excavations at one time. Therefore, a subsequent backfilling of the stope layer by layering is adopted, which results in a layered backfill structure. The purpose of this study was to explore the strength development, stress distribution and deformation across the stope supported by both layered and non-layered backfill. It has been observed that the backfill support system gain its strength with time, however, the layered backfill support system loses its strength when more layers are introduced, this is due to the shearing effect around the interfaces of the backfill layers. The impact of layering was validated by 3D numerical simulation. It is therefore concluded that non layered backfill support system are more suitable for stoping mining methods rather than layered support system. [ABSTRACT FROM AUTHOR]

Traditional mining methods damage the cultivated land and produce gangue waste that often contaminates the environment. Yet, these problems can be mitigated by transforming the waste into gangue-based cemented backfill material (GCBM), whose mechanical properties are crucial for surface protection. Therefore, in this study, an intelligent model based on laboratory tests was developed to evaluate the GCBM's mechanical properties. The strength tests and polynomial response surface model (PRSM) were used to analyze the non-linear correlation between the influencing factors and the uniaxial compressive strength (UCS). Meanwhile, the importance of multidimensional factors was analyzed by the mean impact value, revealing that concentration and gangue proportion are the most sensitive factors. In addition, an intelligent response surface model (IRSM) based on support vector regression model was constructed by enhancing an optimization algorithm with chaotic mapping and adaptive methods. The performance of the traditional PRSM and the novel IRSM was compared, and the IRSM was validated. The IRSM can predict UCS more efficiently and effectively than the traditional PRSM under high-dimensional factors, with R2 of 0.96 and MBE of 0.05. This indicated that the IRSM has the potential to promote coal mine waste reduction and environmental protection. [ABSTRACT FROM AUTHOR]

Reclamation is regarded as one of the mining processes that can lessen the environmental impact of its production, particularly for large-scale coal mines that emit significant quantities of greenhouse gases. However, the assessment and evaluation of the reclamation process primarily rely on qualitative methods. Utilizing LANSAT8 Operational Land Imager (OLI) remote sensing in conjunction with GIS, this study aimed to develop a quantitative method for validating the efficacy of a reclamation procedure applicable to the emerging trend of carbon reduction. The empirical formula utilized to compute the annual carbon sequestrations of the reclamation area in the Mae Moh mine exhibited the appropriate spatial relative standard deviation (S-RSD) at 98.25%. The findings indicate that the reclamation area reached its highest level of carbon sequestration in 2022, at 331.28 ± 11.89 ktCO2e, surpassing the baseline of 126.53 ktCO2e. Furthermore, the approach demonstrates significant potential in improving the standard method for assessing reclamation through reforestation. [ABSTRACT FROM AUTHOR]

Backfill coal mining technology has drawn widespread attention due to its benefits of "controlling surface deformation and subsidence, reducing mining-induced disturbance in the stope, and recycling solid mine wastes". However, the backfill coal mining technology is still progressing slowly in China. The geological environment of China's mining areas is complex and highly diversified, and backfill coal mining is expected to fulfill different goals in a wide range of engineering scenarios. These facts explain the poor reproducibility of backfill coal mining projects. This study reviews the existing backfill coal mining systems in China. Based on findings from a survey of engineering cases, we summarize five types of new backfill coal mining methods classified by deployment style; namely, borehole grouting backfill, roadway backfill, borehole–roadway backfill, in situ backfill, and roadway-in-situ backfill. A total of 15 backfill coal mining methods falling into the above five categories are described. An engineering design workflow for backfill coal mining consisting of five steps is proposed; namely, identifying the targets of backfill, analyzing the feasibility of deploying the backfill system, comparing the engineering quantities of different engineering schemes, estimating the economic efficiency of backfill, and backfill performance tracking and monitoring. Real cases of backfill engineering design are analyzed to inform the fast and reasonable design of backfill strategy for specific working faces in certain coal mines. [ABSTRACT FROM AUTHOR]

This paper conducts impact dynamics experiments on coal measures sandstone in a deep mine via the established dynamic load and temperature split Hopkinson pressure bar (SHPB) experimental system. Firstly, the experimental conditions for the impact dynamics of fine sandstone were determined, with temperatures of 18, 40, 60, 80, and 100 °C, an axial static load range of 1–9 MPa, and a preset bullet incidence velocity of 1.0–5.0 m/s. Secondly, based on the analysis of the basic parameters and physical composition, the dynamic stress and strain responses of fine sandstone under different experimental conditions were obtained, and the change mechanism of its dynamic mechanical process was theoretically analyzed. When the temperature rose from 18 °C to 100 °C, the dynamic peak stress of fine sandstone increased from 36.04 MPa to 73.41 MPa, with an increase of 103.7%. At a temperature of 40 °C, when the axial static load increased from 1 MPa to 9 MPa, the dynamic stress peak of fine sandstone increased from 57.25 MPa to 80.01 MPa, and the corresponding peak strain also showed an increasing trend. The experiment analyzed the variation characteristics of dynamic stress in fine sandstone under the combined action of different strain rates or bullet incidence velocities and different temperatures. In the strain rate range of 47.1 s−1 to 140.9 s−1, there was a significant strain rate effect on the dynamic peak stress and peak strain of fine sandstone, which increased with the increase of strain rate. The study found a polynomial relationship between the dynamic mechanical parameters of fine sandstone and the impact of experimental parameters, with a coefficient of determination greater than 0.9. A dynamic stress constitutive model for fine sandstone under one-dimensional stress state under dynamic load and temperature action was established, and the model validation and parameter determination of dynamic stress changes in fine sandstone under different temperature conditions were carried out. The research results provide a new experimental method for the static and dynamic mechanical analysis of coal and rock masses under complex geological conditions and can provide a basic reference for the prevention and control of dynamic disasters in deep mining processes. [ABSTRACT FROM AUTHOR]

A comprehensive evaluation method is proposed to analyze dust pollution generated in the production process of mines. The method employs an optimized image-processing and deep learning framework to characterize the gray and fractal features in dust images. The research reveals both linear and logarithmic correlations between the gray features, fractal dimension, and dust mass, while employing Chauvenel criteria and arithmetic averaging to minimize data discreteness. An integrated hazardous index is developed, including a logarithmic correlation between the index and dust mass, and a four-category dataset is subsequently prepared for the deep learning framework. Based on the range of the hazardous index, the dust images are divided into four categories. Subsequently, a dust risk classification system is established using the deep learning model, which exhibits a high degree of performance after the training process. Notably, the model achieves a testing accuracy of 95.3%, indicating its effectiveness in classifying different levels of dust pollution, and the precision, recall, and F1-score of the system confirm its reliability in analyzing dust pollution. Overall, the proposed method provides a reliable and efficient way to monitor and analyze dust pollution in mines. [ABSTRACT FROM AUTHOR]

The novel ternary composites BiOBr-TiO2-attapulgite (BTA) were synthesized using a simple hydrothermal and water-bath method, exhibiting excellent photocatalytic performance to multiple xanthates. For the BTA photocatalyst, TiO2 and BiOBr were uniformly loaded onto the surface of acid-activated attapulgite. As a widely used collector in mining processes, sodium ethyl-xanthate (SEX) was selected as the target pollutant due to its high toxicity. The BTA ternary photocatalyst demonstrated significantly higher adsorption and photocatalytic degradation performance compared to TiO2 nanoparticles, BiOBr nanosheets, and BiOBr-TiO2 heterojunction. Structural characterization and experimental results indicated that the exceptional photocatalytic degradation efficiency of BTA was mainly attributed to the formation of a heterojunction between BiOBr and TiO2, as well as the presence of additional active adsorption sites provided by attapulgite. Free radical scavenging experiments and EPR results confirmed that the photogenerated holes were the predominant active species in photodegrading SEX throughout the entire experiment. The LC-MS results provided insight into potential degradation pathways of SEX. This research demonstrates that BTA, as a novel triple composite material, achieves rapid and complete degradation to 20 mg/L SEX within 20 min. This work presents a novel approach to synthesize mineral-based photocatalysts, which have broad prospects for application in flotation wastewater treatment. [ABSTRACT FROM AUTHOR]

• Exploring pedestrian crash patterns at night is a noteworthy ongoing traffic safety concern. • Association Rules Mining methodology is utilized to reveal the association of crash-contributing factors separately at the intersection and segment locations. • This study utilized 5 years (2015–2019) of pedestrian fatal and severe injury crashes in Louisiana that occurred at night. • At the intersection, a few critical contributing factors are – driver/pedestrian alcohol involvement, driver age (15–24, >64), pedestrian age (<15, >64), and rainy weather conditions. • At the segments, a few critical contributing factors are – dark lighting conditions, open country location, high posted speed limit, interstate, and two-way roads with no physical separation. Introduction : Pedestrian safety at nighttime is an ongoing critical traffic safety concern. Although poor visibility is primarily associated with nighttime pedestrian crashes, other contributing factors such as humans, vehicles, roadways, and environmental factors interact with each other to cause a crash. Additionally, the pattern of nighttime pedestrian crashes differs significantly according to the intersection and segment location, which requires further exploration. Data: This study applied Association Rules Mining (ARM), a rule-based machine learning method, to reveal the association of nighttime pedestrian crash risk factors according to the intersection and segment locations using 2,505 nighttime pedestrian fatal and injury crashes in Louisiana (2015–2019). Results and conclusions: Based on the generated rules, the results show that nighttime pedestrian crashes at the intersection are associated with right-turn vehicle movement, older drivers (>64 years) at the high-speed intersection, senior pedestrians (>64 years) in rainy weather conditions, violation by pedestrian age group '<15 years', and alcohol-intoxicated pedestrian violation in business/industrial areas. Additionally, 'careless operation' at the intersection is associated with alcohol-involved drivers. Most of the nighttime pedestrian crashes at segments are associated with roadways with no physical separation and the absence of streetlights. Driver alcohol involvement and their physical condition (inattentive/distracted) are also associated with pedestrian crashes associated at the segment location at night. Other segment pedestrian crashes are linked to the interstate in dark conditions, open country locations, and high-speed roadways. Additionally, the crash site investigation identified several critical pedestrian safety concerns including the lack of crosswalk facilities, high driveway density, and pedestrian behavioral patterns (e.g., crossing at roadway segments close to the intersection location). Practical Applications: The findings of this study can be used for selecting the appropriate countermeasures based on a case-by-case basis. The exposure patterns can be used in educational campaigns to strategically reduce nighttime pedestrian crashes. [ABSTRACT FROM AUTHOR]

Coal mining is generally carried out through open pit mining methods which have an impact and become an obstacle to changes in the chemical, physical, and biological properties of the soil. Revegetation of reclaimed land is a priority in restoring ecosystems disrupted by mining activities. This study aims to assess the success of the direct planting method in accelerating the growth of Pterocarpus indicus plants in coal mining reclamation areas. Field data and observations are used to evaluate the growth of plants directly planted in reclaimed post-mining land. The growth parameters observed include plant height, stem diameter, and leaf count using both seedling and stemcutting planting materials. The research results indicate that the direct planting method has a significant impact on accelerating the growth of Pterocarpus indicus plants. The plant height, diameter, and leaf count growth from the ANOVA test results showed a significant effect or significance at p<0.05 for the interaction between planting material, fertilizer, and dosage. The Duncan test results for the average plant height, stem diameter, and leaf count indicate the optimal use of bokashi fertilizer. The effective bokashi fertilizer dosage for each variable is 3 kg/planting hole, resulting in a plant height of 102.31 cm; 3 kg/planting hole, resulting in a stem diameter of 24.26 cm; and 5 kg/planting hole, resulting in a leaf count of 41.32. [ABSTRACT FROM AUTHOR]

Urban mining has emerged as a concept that goes beyond conventional recycling, as it aims to tackle both the challenges of solid waste generation and management, as well as the scarcity of primary resources. Gravity concentration has gained increasing attention as a promising method for addressing crucial challenges in urban mining applications. In this sense, this review provides a comprehensive and up-to-date overview of gravity concentration in urban mining processes, covering principles, techniques, current applications, recent advancements, challenges, and opportunities. Emphasis was placed on shifting from the commonly found literature focus on ore processing to solid waste processing. Three types of solid waste, namely plastics, construction and demolition waste (CDW), and waste from electrical and electronic equipment (WEEE), were chosen for a more in-depth examination due to their massive production and widespread generation. Discussions also considered the potential of gravity concentration to address the unique challenges in their processing and explored possibilities for future developments. [ABSTRACT FROM AUTHOR]

At present, when addressing the problem of fault stability in mines, most attention is paid to the study of the impact of a single mining method on faults. In order to study fault stability in mines more comprehensively, this paper researches the effect of coordinated mining using multiple mining methods. For example, the sublevel caving method without the sill pillar and the lower-layer filling method of coordinated mining can be used to analyze the dynamic response law of the fault, as well as the stability of the fault in different mining conditions. In this paper, the stress field, displacement field and sliding trend index of the fault plane and orebody near the fault are obtained via numerical simulation and theoretical analysis methods, and the main factors affecting fault stability under different mining conditions are analyzed. The results show that under the influence of cooperative mining, the shear stress fluctuation of the fault surface and the ore body near the fault increase gradually with the sublevel height of the sublevel caving method without the sill pillar and the lower-layer filling method, and the indexes of slip tendency become larger, which may be a precursor of fault activation. In particular, the fault surface of the sublevel caving method without the sill pillar reflects the drastic change in the shear stress with the larger displacement, and the instability brought to the fault by the sublevel caving method without the sill pillar is greater than that brought to the fault by the lower layer filling method under the premise of only changing the height of the sublevel. [ABSTRACT FROM AUTHOR]

This article presents a new system of systems for sequestering carbon using a novel combination of existing technologies of biomass pyrolysis and cemented paste backfill, without any detriment to the performance of either process. Biochar production from waste biomass is discussed. This can be any production system using any locally available waste product; the absolute quality of biomass is not strictly necessary. A review of the effects of low concentration dosage on cementitious materials is presented, citing several existing research and demonstration projects. We argue that the use of biochar in mine backfill at 2 wt.% provides the best potential for a more economic backfill paste compound, without loss of physical or mechanical properties, that can offer a climate-significant opportunity to move closer to satisfying net zero commitments. Biomass production from waste and industrial sized mining processes are able to be easily co-located in multiple countries around the world. We propose that this new backfill recipe allows any provider to contribute to net-zero targets with an environmentally positive impact. [ABSTRACT FROM AUTHOR]

Backgrounds: The transportation system within any mining project, which is responsible for delivering extracted ore to the crushing units or wastes to the wasting dumps as the destinations, poses a significant challenge in mining processes. On one hand, there are various transportation systems, notably the Truck–Shovel, the traditional method, and relatively newer and less common In-Pit Crushing and Conveying (IPCC) systems. On the other hand, choosing the most suitable system for a specific mining project depends on various factors, with technical aspects being one of the most critical. While there is extensive research on the Truck–Shovel system from a technical perspective, there is relatively limited research on IPCC systems. Methods: This research aims to carry out a comparative analysis of different transportation systems, encompassing Truck–Shovel, Fixed In-Pit Crushing and Conveying (FIPCC), Semi-Fixed In-Pit Crushing and Conveying (SFIPCC), Semi-Mobile In-Pit Crushing and Conveying (SMIPCC), and Fully Mobile In-Pit Crushing and Conveying (FMIPCC) systems. To achieve this goal, a technical index is introduced, which is based on three elements: the availability and the utilization of the system, as well as the consumption of power. This index will be developed as a system dynamics model, enabling the observation of each system's performance throughout the operational lifespan of the mine. Results: Ultimately, based on the proposed method, the most effective transportation system based on the defined technical index can be identified at any time of the project. In this research, the Truck–Shovel system generally selected as the most preferred transportation system, except for two different periods. Conclusions: This study could successfully perform the selection among different transportation systems. Nevertheless, it was modeled and performed in a deterministic environment, but still the stochastic nature of the processes can be another topic of research. [ABSTRACT FROM AUTHOR]

Approximately 50% of the world's uranium is mined in a closed way using underground well leaching. In the process of uranium mining at formation-infiltration deposits, an important role is played by the correct identification of the formation of reservoir oxidation zones (ROZs), within which the uranium content is extremely low and which affect the determination of ore reserves and subsequent mining processes. The currently used methodology for identifying ROZs requires the use of highly skilled labor and resource-intensive studies using neutron fission logging; therefore, it is not always performed. At the same time, the available electrical logging measurements data collected in the process of geophysical well surveys and exploration well data can be effectively used to identify ROZs using machine learning models. This study presents a solution to the problem of detecting ROZs in uranium deposits using ensemble machine learning methods. This method provides an index of weighted harmonic measure (f1_weighted) in the range from 0.72 to 0.93 (XGB classifier), and sufficient stability at different ratios of objects in the input dataset. The obtained results demonstrate the potential for practical use of this method for detecting ROZs in formation-infiltration uranium deposits using ensemble machine learning. [ABSTRACT FROM AUTHOR]

The solar salt mining process involves collecting salt water from the sea and trapping it in an interlinked network of shallow ponds where the sun evaporates most of the water. As soon as the brine reaches its saturation point, salt crystallisation occurs. Several factors influence this mining process, each with a degree of variability that results in a risk factor owing to uncertainty. This study proposes a two-stage stochastic programming model, called 'a recourse model', that maximises salt crystallisation while providing solutions that are hedges against uncertainty. First, the theoretical background on optimisation theory is provided, followed by an overview of the mining processes. Second, the recourse model is verified and validated using historical data and comparing the results with its deterministic counterpart. The main contribution of this study is the formulation of the recourse model and the value that this approach adds when dealing with uncertainty in any decision-making process. [ABSTRACT FROM AUTHOR]

Communities and authorities have been dismayed by globally recorded tailings storage facility (TSF) failures in recent years, which have negatively affected the safety of people and the integrity of the environment. In this context, obtaining the social and environmental license to operate TSFs has become a challenging process for mining companies. This has promoted the trend of using mine tailings dewatering technologies in the mining industry, with dry stacking of filtered mine tailings being recognized worldwide as one of the most acceptable, safe, and environmentally friendly solutions. This article presents a new paradigm in managing mine tailings, with disruptive and futuristic characteristics, considering the dry stacking of filtered mine tailings for large-scale industrial production rates over 100,000 metric tons per day (mtpd). Aspects of filtered tailings management are discussed, such as (i) dewatering process plant with thickening/filtering equipment, (ii) conveyance using fixed and movable conveyor belts, (iii) construction of dry stacking of filtered mine tailings facility, and (iv) implementation of Industry 4.0 technologies for automation of the mining processes. Finally, the article discusses how the large-scale filtered mine tailings solution is applied, considering the advances in the equipment's performance and implementation of Industry 4.0 technologies as well as the experience gained worldwide in several mining operations. The future global trend is that mining operations with high daily production of mine tailings will apply dry stacking technology without dams to guarantee sustainability, promote continuity of the mining business, ensure the safety of communities, and conserve the environment. [ABSTRACT FROM AUTHOR]

Coal mining activities are causing an extensive range of environmental issues at both operating and abandoned mine sites. It is one of the most environmentally destructive practices, with the capability to eliminate fauna and flora, impact the groundwater system, and pollute the soil, air, and water. The Czech Republic relies almost exclusively on coal as its primary domestic source of energy. The combined reserves of hard and brown coals in this country are 705 million tons. About 50 million tons of coal is produced annually, making it the 14th biggest producer in the world. Soil degradation is an inevitable outcome of the coal production from surface coal mining procedures in the Czech Republic. Significant changes have taken place in soil productivity, hydraulic characteristics, horizon, and texture as a result of soil pollution, bioturbation, compaction, and weathering. The current review has evaluated the impact of reclamation and coal mining on soil characteristics, including biological, chemical, and physical properties. Additionally, the study has outlined the process of soil formation in reclamation areas in the Czech Republic. In nutshell, research gaps and future directions in understanding coal mining areas and their influences on soils in the Czech Republic are identified. [ABSTRACT FROM AUTHOR]

A reliable design of stopes is critical to ensure both safety and efficiency in mining operations. The evolving mining methods and technologies as well as increasing mining depth dictate the need to continually improve stope designs. This paper presents a comprehensive review in order to compare and consolidate various stope design methods. This review covers various aspects of stope design, including design principles, factors to consider, and the diverse range of design methods available. The results led to the classification of various methods encompassing engineering analogies, fundamentals, numerical simulations, and industrial tests. Of particular significance, the review furnishes detailed insights into the research conducted on each method, as well as each method's practical performance in engineering applications. Furthermore, the review highlights the inherent limitations in current design methods and suggests potential avenues for future research. Finally, by comprehensively considering the functional roles and advantages of each design method, it overcomes the limitations of relying solely on a single method for stope structural parameter design, and a general process is proposed. [ABSTRACT FROM AUTHOR]

Programmers who work with smart contract development often encounter challenges in reusing code from repositories. This is due to the presence of two unknowns that can lead to non-functional and functional failures. These unknowns are implicit collaborations between functions and subtle differences among similar functions. Current code mining methods can extract syntax and semantic knowledge (known knowledge), but they cannot uncover these unknowns due to a significant gap between the known and the unknown. To address this issue, we formulate knowledge acquisition as a knowledge deduction task and propose an analytic flow that uses the function clone as a bridge to gradually deduce the known knowledge into the problem-solving knowledge that can reveal the unknowns. This flow comprises five methods: clone detection, co-occurrence probability calculation, function usage frequency accumulation, description propagation, and control flow graph annotation. This provides a systematic and coherent approach to knowledge deduction. We then structure all of the knowledge into a semantic-enriched code Knowledge Graph (KG) and integrate this KG into two software engineering tasks: code recommendation and crowd-scaled coding practice checking. As a proof of concept, we apply our approach to 5,140 smart contract files available on Etherscan.io and confirm high accuracy of our KG construction steps. In our experiments, our code KG effectively improved code recommendation accuracy by 6% to 45%, increased diversity by 61% to 102%, and enhanced NDCG by 1% to 21%. Furthermore, compared to traditional analysis tools and the debugging-with-the-crowd method, our KG improved time efficiency by 30 to 380 seconds, vulnerability determination accuracy by 20% to 33%, and vulnerability fixing accuracy by 24% to 40% for novice developers who identified and fixed vulnerable smart contract functions. [ABSTRACT FROM AUTHOR]

In the forthcoming era of fully autonomous mining, spanning from drilling operations to port logistics, novel approaches will be essential to pre-empt hazardous situations in the absence of human intervention. The progression towards complete autonomy in mining operations must have meticulous approaches and uncompromised security. By ensuring a secure transition, the mining industry can navigate the transformative shift towards autonomy while upholding the highest standards of safety and operational reliability. Experiments involving autonomous pathways for mining machinery that utilize AI for route optimization demonstrate a higher speed capacity than manually operated approaches; this translates to enhanced productivity, subsequently fostering increased production capacity to meet the rising demand for metals. Nonetheless, accelerated wear on crucial elements like tires, brakes, and bearings on mining machines has been observed. Autonomous mining processes will require smarter machines without humans that guide and support actions prior to a hazardous situation occurring. This paper will delve into a comprehensive perspective on the safety of autonomous mining machines by using Bayesian networks (BN) to detect possible hazard fires. The BN is tuned with a combination of empirical field data and laboratory data. Various faults have been recognized, and their correlation with the measurements has been established. [ABSTRACT FROM AUTHOR]

Abstract Kansei Engineering (KE) has shown its prominent applicability in service design and development, focusing on translating and interpreting customers’ emotional needs (Kansei) into service characteristics. It is critical and promising as the services sector has grown faster than the manufacturing sector in developing economies in the past three decades. It accounted for an average of 55% of GDP in some developing economies. KE’s flexibility in collaborating with other methods and covering various service settings shows its unique superiority. However, there is criticism of the collected Kansei’s validity and the proposed solution’s robustness. It might be potentially caused by the dynamics of customer emotional needs and various service settings. As a result, Kansei is found to be somewhat fuzzy, unclear, and ambiguous. Hence, a more structured KE methodology incorporating the Kansei text mining process for robust service design is proposed. Kansei text mining approach will extract and summarize service attributes and their corresponding affective responses based on the online product descriptions and customer reviews. The Taguchi method will support the robustness of the proposed improvement strategy. An empirical study of a zoo as a tourism attraction service and its practical implication is discussed and validated in the proposed integrative framework. [ABSTRACT FROM AUTHOR]

To quantitatively evaluate the carbon emission effects of various underground mining schemes in metal mines, a carbon emission calculation model specifically for underground metal mines was established. The carbon emissions stemming from the mine's production process were categorized into three components: carbon emissions from the production of consumed materials, fuel, and electricity; carbon emissions resulting from fuel combustion and explosive explosions, and the reduction of CO2 absorption due to the occupation of the surface industrial site. Subsequently, the carbon emission impact of underground metal mines was assessed using an example from an iron mine in Anhui Province, China. The results showed: (1) Among the underground mining processes, electricity consumption emerged as the primary source of carbon emissions. This underscores the potential for significant carbon emission reduction through the implementation of innovative electric power technologies in underground metal mines. (2) Mining methods with higher productivity showed clear advantages. They not only contribute to the reduction of carbon emissions per kiloton of ore from multiple perspectives but also led to a shorter mine lifespan and decreased CO2 absorption by woodlands occupied by the surface industrial site. Furthermore, these methods resulted in lower carbon emissions throughout the mine's lifespan. (3) Backfill mining proved to be effective in curbing tailings emissions and reducing the required area for a tailings pond. Consequently, this approach minimizes the CO2 absorption by woodlands occupied by the tailings pond. [ABSTRACT FROM AUTHOR]

The process of digitalization in Ukraine is slow, so studying the state of digitalization of the mining industry is a very relevant issue and will help increase the competitiveness and efficiency of enterprises, which is important for the development of the national economy. The research aims to the state of mining industry digitalization in Ukraine, develop an effective methodology for volumetric modelling of open-pit mining enterprises, and implement an effective digital modelling system. Research methods include analysis of literature sources, factor and situational analysis, comparative economic analysis, system analysis of software, and digital modelling of the enterprise system. Mining and geological data processing and mathematical modelling were used to obtain the following results: the data were digitized, a polygon database was built, the area of the ore body was determined, the cut planes were constructed and drilling and blasting operations were modelled. The creation of a frame and block model of the deposit is investigated and a methodology for block modelling of mineral quality is proposed, which will allow for high-reliability zoning of technological types of minerals in the quarry. Implementing an integrated software system for the digital modelling of the deposit will enable efficient visualization of the distribution of useful components, resulting in improved competitiveness and modernized planning and management of mining processes. The proposed block modelling methodology for the open pit space further enhances the practical value of the study. [ABSTRACT FROM AUTHOR]

Due to the particularity of the occurrence characteristics of shallow multiseam mining, underground mining space is vulnerable to obvious roof behaviors and serious gas anomalies, which are closely related to the destruction and migration characteristics of the overlying strata, the characteristics of the overlying-strata-bearing structure, and the permeability distribution of the broken interlayer under the influence of the overlying-strata-bearing structure. However, the related research is still insufficient. In this work, the discrete-element method (DEM) numerical model was used to simulate the entire process of the continuous mining of a shallow multiseam. In addition, the gas migration and its distribution in the lower mining field, under the influence of low-oxygen (O2) gas intrusion into the upper goaf, and the air leakage flow in the working face were studied using a Particle-Flow Code (PFC)–COMSOL coupling method. The results showed that the main feature in the evolution of the overlying-strata-bearing structure was the dynamic change in the supporting relationship between the collapse area and the surrounding rock, which changed from complete support to local force conduction, and finally complete separation under continuous mining in the upper and lower coal seams. The load distribution of the coal-seam floor presented a continuous change from surrounding rock to inside the goaf, with the breaking angle of the overlying strata being the key influencing factor. The conjoint analysis of stress and porosity indicated that the load under the overlying-strata-bearing structure determined the permeability distribution of the broken interlayer, which gave the gas in the goaf obvious distribution characteristics. [ABSTRACT FROM AUTHOR]

In the field of multi-attribute group decision-making (MAGDM), "decision-making trial and evaluation laboratory" (DEMATEL) is a popular method that has been deployed to discover hidden relationships among many inter-twined factors of numerous real-world problems. This paper discusses several limitations of the DEMATEL method in mining the causal relationships and ranking the factors. Also, in this paper, we develop a novel decision-making framework that will be able to overcome the issues found in the DEMATEL method and tackle both formal and informal decisions. This model, which we call "Causal Relationship and Ranking Technique (CRRT)", uses a data-deterministic expert weighing setup rather than assigning equal weights or pre-defined weights to each expert. The model proposes a better technique to mine factor inter-relations and proposes two new types of digraphs portraying the causal inter-relationships among the factors, and also proposes a new two-step factor ranking method based on the derived causal relationships. The intuitionistic fuzzy setting is considered in this work in order to capture the uncertainty of expert opinions. Furthermore, our proposed framework is applied to a real-life case study on discovering various factors of a high school administration, that have a significant influence on students' performance. Comparison with standard methods such as TOPSIS and VIKOR for student performance data and also some other datasets such as supplier selection data, and sustainability data proves that the model is able to rank the factors better than the existing models. [ABSTRACT FROM AUTHOR]

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The paper analyzes the positive and negative aspects of various technological solutions for the liquid brines used during the development of polymineral potash ore deposits and considers the problem of determining the choice of the optimal approach by considering geological, technical, environmental, and financial factors. The study of the issues of utilization and reduction of the liquid brines components of discharges in the production of potash fertilizers, the simultaneous reduction of valuable components loss with liquid discharges, and, due to this, increasing the production of potash fertilizers, and the usage in the technology of mine brines, are an urgent and important scientific and engineering challenge of the potash industry. Technologically, several alternative solutions can reduce the number of liquid by-products placed in sludge storage. The work used analytical methods, including statistical data processing, modeling, pre-design studies of technological solutions, and assessment of economic costs. Excess brines of potash mining and processing plants are liquid waste obtained during the production of potash fertilizers – MOP и SOP. The accumulation of excess brines in sludge storage facilities is estimated at millions of cubic meters per year. However, the expansion of the sludge storage facilities area and the construction of dams are only temporary solutions. They are associated with risks in the design, construction, and operation of hydraulic structures, increasing the risks of brine leakage into open and underground water basins. Therefore, it makes it necessary to use other methods of brine disposal. Depending on the nature of the processed polymineral potash ores, several methods can be combined to dispose of excess brines at once: backfilling, osmosis, injection into deep horizons, and multistage evaporation. The most optimal combination of brine reduction technologies for potassium-magnesium processing plant's raw materials is the following: 60% is disposed of by usage of vacuum evaporation units, 20 % by injecting excessive brines into deep absorbing horizons, and 10%—20% should be used for backfilling or additional products production. [ABSTRACT FROM AUTHOR]

Sampling is an important tool for gathering information about mineral deposits, helping to estimate the ore grade, and has great relevance at any stage of a mining project, to ensure reliable results and consequently, to project a better mining planning. There are several errors to which the sampling is exposed and among them we can mention the fundamental sampling error (FSE). This error cannot become zero as it is related to the constitutional heterogeneity of the ore, so it represents the minimum sampling error. This study applies Pierre Gy's theory of sampling (TOS) to estimate the values of K and a sampling constants at different deposits of bauxite in Brazil and compare them with the calculated factors, then calculate the relative standard deviation of the fundamental sampling error s(FSE) based on the results of the heterogeneity test (HT) in each deposit. The deposits are located in: Barro Alto - State of Goiás, Juruti - State of Pará, and Poços de Caldas - State of Minas Gerais. The weathering process is the main reason of the alteration of the physical and chemical factors diversifying bauxites in Brazil and worldwide. However, when sampling is carried out correctly, the Gy's formula becomes a powerful tool for improving mining processes as long as the factors are estimated correctly for each ore. [ABSTRACT FROM AUTHOR]

Induced polarization (IP) is a common method in ore exploration. IP spectra measured over a wide frequency range can be used to characterize material properties of ores, slags and other residual material from mines and processing facilities. Previous studies have shown that IP parameters are sensitive to type, content or grain size of electronically conductive or semi-conductive minerals. Up to now, a variety of experiments has been performed on sand mixtures with fractions of ore minerals. Most experiments consider only a single fraction with a fixed grain size. We continue a series of experiments that have been done with sand–pyrite mixtures. The presented study compares IP spectra recorded for samples either with a single grain radius fraction (E-samples) or with two different grain radii fractions (Z-samples). The spectra are fitted to Pelton models. A Debye decomposition that provides a relaxation time distribution (RTD) is applied to the complex conductivity spectra. The RTD indicates separated maxima only if the ratio of mean grain radii is larger than a factor five. The resolution of the phase spectra and the spectra of imaginary part of conductivity is lower. Even though the volumetric pyrite content is equal in each fraction, the phase spectra and RTD of the Z-samples indicate much higher signals for the pyrite fraction with smaller grain radius. The same observation is made for the chargeability that shows larger values for decreasing grain radii. This finding contradicts existing theories that consider the chargeability as a suitable proxy of the volumetric content of ore minerals. We explain the observed effect by an interaction between neighbouring pyrite particles. The conductivity of the mixtures of the E-samples increases with decreasing grain radius of the pyrite fraction. This effect is attributed to dissolution effects on the surface of the pyrite particles during the sample preparation. We find that the additive superposition of the phase spectra of two E-samples is in good agreement with the measured phase spectra of the Z-samples (measured superposition) containing the two corresponding pyrite fractions. The agreement is slightly worse for the spectra of imaginary part of conductivity, where the measured superposition overestimates the mathematical superposition. The experimental results of our study motivate a further improvement of existing mechanistic models. [ABSTRACT FROM AUTHOR]

Mine safety evaluation (MSE) is a complicated engineering problem that may contain the truth, falsity, and indeterminacy information. In the process of mine safety evaluation, the linguistic neutrosophic multivalued information can conveniently express the truth, falsity, and indeterminacy linguistic values and satisfy the thinking and expression habits of decision makers. Then, existing probabilistic linguistic neutrosophic decision-making methods are difficult to reveal the real probability values in several linguistic evaluation values. To reasonably simplify the expression and operation of the linguistic neutrosophic multivalued information and overcome the defects of the probability methods, the aim of this study is to propose a safety evaluation method of mines using correlation coefficients of consistency linguistic neutrosophic sets (CLNSs) in the setting of linguistic neutrosophic multivalued sets (LNMVSs). To do so, this study first defines LNMVS based on truth, falsity, and indeterminacy linguistic multivalued sequences with identical and/or different linguistic values, and then proposes a transformation method from LNMVS to CLNS based on the average values and consistency degrees (complement of standard deviation) of the linguistic multivalued sequences to reasonably simplify the information expression and operations of LNMVSs. Next, correlation coefficients between CLNSs and their MSE method are developed to solve MSE problems. By an actual example about the safety assessment of metal mines and relative comparative analysis, the evaluated results reveal that the proposed MSE method can reasonably and effectively deal with safety evaluation problems of the mines in the setting of LNMVSs. The proposed method can not only reflect the mean and consistency information of multiple language evaluation values and overcome the defect of unreasonable information generated by the probabilistic language method in small evaluation data, but also make evaluation results more effective and credible. [ABSTRACT FROM AUTHOR]

Mining has proven to be a controversial form of resource development throughout the circumpolar north. This article compares two mining projects—the proposed Prosperity gold and copper mine in central British Columbia, Canada and the proposed Kallak iron ore mine in Norrbotten County in northern Sweden—that have endured long and protracted approval processes that have caused tensions and disputes between mining companies, Indigenous peoples, communities and state actors. In an effort understand the particular development paths taken by these two mining projects, this article examines the institutional determinants that structure relationships between industry, Indigenous communities and the state in Canada and Sweden. Using an historical institutionalist theoretical approach, the article focuses on the manner in which the structural features of the political systems and the environmental assessment and permitting processes in both countries have shaped the mine approval process. It also identifies particular critical junctures—important events and decisions that influenced the trajectory of the approval processes in profound and consequential ways. The article finds that institutional determinants, both historical and contemporary, have played a critical role in determining outcomes in both cases. In particular, it demonstrates the ways in which the structures of the Canadian and Swedish political systems have historically excluded Indigenous peoples from the decision-making process for resource development projects such as mines. It also shows how broader institutional contexts, as well as specific events and decisions, have complicated and politicized the mine approval processes, a situation that has heightened tensions on all sides. [ABSTRACT FROM AUTHOR]

Gossan discarded from mining processes result in metal resource wastage, and its long-term stacking causes environmental hazards. Therefore, this article considers zinc-containing gossan as the research object. The ore was roasted to prepare primary zinc ferrite products and sulfuric acid leaching was performed for purification. Then, XRD analysis was performed to characterize the purified products. The results indicated that the effect of sulfuric acid concentration on the purification of the products was related to its zinc ferrite content. Furthermore, the effect of leaching temperature on the purification of zinc ferrite products was related to sulfuric acid concentration; the lower the sulfuric acid concentration, the more considerable the effect of leaching temperature. The conditions suitable for purifying the products through sulfuric acid leaching are as follows: sulfuric acid concentration of 140 g/L, liquid–solid ratio of 4:1, leaching temperature of 80 °C, leaching time of 120 min, and stirring speed of 300 rpm. This article determines the factors affecting the purification of zinc ferrite by sulfuric acid leaching along with the optimal purification conditions. The findings presented herein provide a theoretical foundation for the development of new processes for preparing zinc ferrite, which has considerable industrial application value. [ABSTRACT FROM AUTHOR]

Subsidence data acquisition methods are crucial to mining subsidence research and an essential component of achieving the goal of environmentally friendly coal mining. The origin and history of the existing methods of field monitoring, calculation, and simulation were introduced. It summarized and analyzed the main applications, flaws and solutions, and improvements of these methods. Based on this analysis, the future developing directions of subsidence data acquisition methods were prospected and suggested. The subsidence monitoring methods have evolved from conventional ground monitoring to combined methods involving ground-based, space-based, and air-based measurements. While the conventional methods are mature in technology and reliable in accuracy, emerging remote sensing technologies have obvious advantages in terms of reducing field workload and increasing data coverage. However, these remote sensing methods require further technological development to be more suitable for monitoring mining subsidence. The existing subsidence calculation methods have been applied to various geological and mining conditions, and many improvements have already been made. In the future, more attention should be paid to unifying the studies of calculation methods and mechanical principles. The simulation methods are quite dependent on the similarity of the model to the site conditions and are generally used as an auxiliary data source for subsidence studies. The cross-disciplinary studies between subsidence data acquisition methods and other technologies should be given serious consideration, as they can be expected to lead to breakthroughs in areas such as theories, devices, software, and other aspects. [ABSTRACT FROM AUTHOR]