Large Mining Research Articles

Proof of Work with Random Selection (PoWR): An Energy Saving Consensus Algorithm with Proof of Work and the Random Selection Function

Bitcoin, which has been used for 13 years, has a role in transactions and investments as a major cryptocurrency. However, as the number of users increases, Bitcoin faces difficulties, such as scalability for transaction throughput and energy-consumption problems due to the concentration of the mining pool. When Bitcoin first started to come out, it began to develop gradually through the mining of individuals. Nevertheless, as the price of the cryptocurrency gradually climbed, large mining corporation groups entered the mining competition with integrated circuit (IC) chips. Consequently, the substantial increase in power consumption is raising concerns regarding energy expenditure. This paper confirms that the verifiable random selection consensus protocol based on proof of work facilitates a fair and efficient system, enabling the participation of numerous individual miners in the mining competition while counteracting the monopolization of the hash rate by large mining corporations, thereby preserving the decentralization of mining. The protocol demonstrates the potential to mitigate substantial energy consumption. Moreover, it embodies features that create barriers to the adoption of high-energy-consuming application-specific integrated circuit equipment, significantly diminishing the principal factors contributing to extensive power utilization.

Applying similar modeling to study vehicle exhaust transport in a confined mining space

To scientifically and effectively manage exhaust pollution in underground confined spaces and reduce hazards from personnel exhaust exposure, a systematic study of the distribution characteristics of diesel locomotive exhaust emissions in mines is needed. Aiming at large underground coal mining operations, an experimental platform for the physical simulation of vehicle exhaust transport in restricted spaces is designed and created. The Hongliulin Coal Mine in Shaanxi Province, China, is used as a prototype, and the platform consists of a coal mining face system, ventilation system, exhaust emission system, monitoring and surveillance system, and control platform. The experimental platform with carbon dioxide simulation of diesel exhaust pollution, in the role of different wind speed, the concentration of carbon dioxide is a downward trend, the wind speed is in the low wind speed on the 0.2 m of the concentration difference of 25.75%; the experimental platform exhaust transport process presents a clear “three-zone” change rule; experimental platform carbon dioxide concentration and the field nitrogen dioxide concentration change trend is consistent. The platform functions and features can provide guidance for mine exhaust management and exhaust exposure hazard prevention and control.

Coal‐wall spalling prevention mechanism using advance‐grooving pressure relief in the large‐mining‐height working face of a shallow coal seam

AbstractIn mining, the roof structure of a working face with a large mining height in a shallow‐buried coal seam is prone to cutting instability in front of the support, which causes support crushing and coal‐wall spalling. This study analyzes 2201 working faces with large mining heights in the Haiwan No. 3 Mine by investigating the mechanical response law of coal walls under the transient excitation of roof structure instability. A mechanical model of coal walls under dynamic and static load coupling is established, revealing the formation mechanism of coal wall spalling and its main influencing factors. Prevention and control technologies of advanced grooving and pressure relief are proposed, and grooving parameters are determined. The results show that: During the mining process of large mining height working face in shallow buried coal seam, the step change of static response of coal wall is induced by the transient instability of roof structure, and the high abutment pressure is formed on the coal wall. At the same time, the strain energy and gravitational potential energy of roof cutting instability are released to form a dynamic load. Under the action of dynamic and static load, the plastic failure dissipation power of the coal wall is greater than the critical power, and the coal wall spalling occurs. The main influencing factors are mining load, mining height, and internal friction angle of the coal wall. The method of advanced grooving pressure relief can change the roof structure and coal force mechanism, by cutting off the connection between the coal wall and immediate roof, reducing the height of the coal wall force, effectively controlling the position of the roof cut off break line, reducing the static load effect of the roof on the coal, and transferring the position of the dynamic load response to the depth of the coal wall. When the grooving height‐depth ratio k is 0.75, the peak value of the abutment pressure moves 5.57 m to the front of the working face, and the pressure relief effect is the best. The above research results provide an effective active protection method for controlling coal wall spalling in fully mechanised working face with large mining height.

Exploring Differences in Leadership Behaviors and in the Perceived Work Environment Between Younger and Older Managers in a Swedish Mining Company

AbstractThis study examines differences in leadership behaviors and in the perceived work environment between older and younger managers in a large Swedish mining company. The leadership behaviors and work environment of young managers in the mining industry will become more important in the future due to the changes taking place in the industry. Such changes include the older generation of managers reaching retirement age, while the industry generally finds it difficult to recruit a younger generation of employees. Moreover, rapid technology-centered transition, such as the green transition of the mining industry, is underway which may put young managers in particular under pressure. Meanwhile, research on young managers in the mining industry more broadly is sparse. Data for this study was mainly gathered via a questionnaire, complemented by data from interviews. The questionnaire included 48 validated self-rate questions on background variables, social and organizational working conditions, health, and leadership behavior. The survey was answered by 216 managers (response rate: 63%). Interviews were carried out with ten young managers (35 years or younger). The study found no statistically significant differences between younger and older managers with regards to workload, working hours, health, and work satisfaction. We found that older managers rate themselves higher, at a statistically significant level, for change-oriented leadership behaviors. However, when age is analyzed together with other variables that are significantly different between the two groups, only managerial experience and managerial positions show statistically significant associations with change-oriented and healthy and effective leadership behaviors. The interviews indicate that the young managers encounter challenges that are related to their experience and training, but few are related to their age. Given the influence of managerial experience on leadership behaviors, leadership training appears to be an important area of intervention, and conditions must be improved to enable change-oriented leadership among managers in the mining industry, with a greater focus on young managers.

A Benchmarking Model for HRM Elements of Large Mining Industry: ISM-Based Approach

While human resource management (HRM) elements concerning the expansive mining industry have been acknowledged, they still need to be explored. This paper presents a novel and strategic endeavour to construct a benchmark model linking HRM elements specific to the large mining industry. Drawing from an extensive literature review, crucial HRM elements pertinent to the mineral industry are systematically identified and thoroughly examined. The study utilises the interpretive structural modelling (ISM) technique within the context of major Indian mining industries to unveil latent relationships among these HRM-related elements. Through six-phased interactions, a foundational model is established, illuminating these relationships. The findings are poised to positively impact the mining industry, contributing to enhanced system sustainability. Furthermore, this paper represents a pioneering effort as the first research to elucidate the relationship model of HRM elements within the mining industry. It encourages HRM researchers to delve further into the mining industry to address its challenges. This research serves as a foundational study and provides a platform for further investigations by HRM experts, researchers and field personnel, enabling a multifaceted exploration of HRM perspectives.

Effect of Variation of Dragline Bench Height and Cut Width on Performance of Tandem Dragline Operations in Large Opencast Coal Mines in India

Effect of Variation of Dragline Bench Height and Cut Width on Performance of Tandem Dragline Operations in Large Opencast Coal Mines in India

Modeling and scenario building for climate change adaptation planning: The case of large mining in Chile

The mining sector in Chile is a strategic industrial sector for the country. Existing evidence shows that it faces several serious climate change threats; precipitation and flooding, droughts, heatwaves, among others. This scene put pressure on the government and the industry to develop efficient adaptation plans. To date, adaptation plans are designed under the rather linear paradigm of predict-then-act or the impact-lea approach as they are characterized in the IPCC Assessment Report 5 (AR5). Literature and the IPCC reports have identified the limits of those planning paradigms showing the relevance of adaptation barriers or enabling conditions, which should be considered as intrinsic part of the planning problem.In methodological terms, planning for climate change risks implies an enriched adaptation plan problem, previously characterized only by an operative climate risk management, that must be described at the beginning of the decision-making process. In this study, our objective is to contribute to the climate change adaptation planning of large-scale mining in Chile. The study is based on a climate change adaptation planning approach that overcomes the limitations of the current paradigm. In doing so, we start from the understanding that what emerges as an object of analysis from adding to the climate risks their enabling managing conditions is a social system. The social system whose function is that social climate risk management takes place. Therefore, we call it the Social Management System for Adaptation to Climate Change (SMSACC). As such the SMSACC should be the adaptation planning key object.In the first place we modeled that system applying a qualitative system methodology and then we developed it into a mathematical model based on graph theory, in particular the signed digraphs. This allows us to simulate two types of intervention on the enlarged object of analysis of the large mining adaptation plan. On the one hand, we carried out a future scenario analysis based on prospective tools which enables us to understand the system's answer to different future behavior of its environment, including climate change. On the other hand, we simulate different strategic interventions options on the system, which facilitates understanding the system's reaction under different public policy approaches.The modeling and simulation results provided an insightful understanding of the dilemma of social adaptation management of large mining in Chile, and as such they are useful input for the planning process.

Developing some models to predict the uniaxial compressive strength of various sedimentary rocks (Case studies: Large dam site and mine in Southeast China)

Direct determination of uniaxial compressive strength (UCS) is time-consuming, expensive, and challenging. Therefore, this study aims to indirectly predict UCS using statistical and machine learning methods. First, laboratory measurements were conducted to determine carbonate percentage, water absorption percentage, moisture content, porosity percentage, P-wave velocity, and UCS of sandstone, dolomite, dolomitic limestone, marl limestone, and limestone samples. Subsequently, various models were established to predict UCS using multivariate linear regression (MVLR), random forest regression (RFR), Gaussian process regression (GPR) based on squared exponential kernel function, and adaptive neuro-fuzzy inference system (ANFIS). The influence of Jurassic limestone texture on physical and mechanical properties in stable and unstable slopes in the Three Gorges Dam site and reservoir (TGDSR) showed that the percentage of mudstone texture in unstable slopes is higher than in stable slopes. The UCS, density, compressional wave velocity, and percentage of carbonate in unstable slopes is less than stable slopes. The results indicated that the average measured UCS is 60.60 MPa. Moreover, the average predicted UCS based on the three intelligent methods was 60.55 MPa. The percentage difference between the measured and predicted UCS was −0.09 %, demonstrating that the average error of the three employed methods is less than one percent, highlighting the high accuracy of these methods in estimating rock UCS. Notably, based on error level, Taylor diagram, Wilmot agreement index (WAI), A10 and A20 indices, Nash-Sutcliffe efficiency (NSE), and PM (performance metric) criteria the RFR exhibited superior precision (R2=99 %, and RMSE= 0.06 MPa) compared to the other used methods. The Kruskal-Wallis test (KWT) results showed that there is no significant difference between the measured and predicted values.

A method for optimizing the capacity allocation of a photovoltaic-pumped hydro storage system in an abandoned coal mine

The enormous potential of the photovoltaic (PV) sector has aided in the faster attainment of China's “dual-carbon” aim. However, due to a scarcity of land resources and intermittent fluctuations in solar energy, it has been difficult to build large-scale PV bases, and existing PV systems also suffer from unstable power generation and seasonal fluctuations and are unable to be directly connected to the grid for use. However, abandoned mines with huge surface collapse zones and a large underground mining area offer a potential possibility for constructing photovoltaic-pumped hydro storage (PV-PHS) systems and limiting PV variations. Based on the abandoned mine pumbed hydro storage (AMPHS) potential assessment model and the optimized discrete wavelet decomposition algorithm, this study proposes a dynamic cycle optimization method for the PHS regulation capacity in an abandoned mine PV-PHS hybrid system. This approach is able to determine the optimal regulation capacity of AMPHS on a daily scale while limiting the volatility of the PV-PHS hybrid system. The method was applied to an abandoned mine PV-PHS hybrid system in Zaozhuang City, Shandong Province, and the optimal regulation capacity of the AMPHS was determined to be 88 MWh and 100 % elimination of PV generation volatility was achieved. This also reduces the economic cost by roughly 1.94 × 108 CNY. In addition, it is possible to store an average of 2.32 % of the PV power generated and to extend the power generation time by approximately 2.5 h per day. This research is critical for boosting the resource use of abandoned mines, and establishing the comprehensive usage model of new energy and abandoned mine resources.

A Stochastic Energy-Efficient Robust Simulation-Based Truck Dispatching Optimization for Simultaneous GHG Mitigation and Operational Excellence in Open-Pit Mines

Almost all currently active large open-pit mines across the globe heavily rely on fleet of shovels and haul trucks for material handling. This material handling system has a significant contribution not only to the production cost of the mine (+50%), but also to its energy consumption (+41%) and greenhouse gas (GHG) emissions (+37%). However, traditionally, operation management in general and truck dispatching, in particular, focused primarily on production targets and operational efficiency, neglecting environmental considerations in open-pit mines. Nowadays, growing awareness of climate change and responsible resource extraction has shifted, however, the focus towards sustainable practices throughout the mining industry, open-pit mining not excluded. The significant contribution of this study lies in the development of an integrated simulation and optimization framework that simultaneously accounts for anthropogenic GHG emissions resulting from energy (fuel) consumption and enhances the operational efficiency of the material handling system, thus yielding direct economic and environmental benefits. The paper fulfills its goals with the aim of simultaneous achievement of four interdependent objectives: minimizing the deviations from target production rates set by strategic plans, minimizing the shovel idle time, minimizing the truck wait time, and minimizing the truck fuel consumption. The performance and the robustness of the proposed framework has been evaluated in a case study at Gol-E-Gohar mine in Iran, demonstrating a successful achievement of up to 6% reduction in fuel consumption per tonne of production leading to a significant overall decrease of up to 20,000 liters in fuel consumption, equivalent to 61,000 carbon dioxide (CO2) emissions, in a 10-day operation with 12 hours of operation per day.

An ICT-enabled community oriented primary care intervention in mining communities during COVID-19 (2019–2022): perceived changes in the role and place of community health workers

BackgroundThis is a study of service provider perceptions of the place, role and practices of CHWs in a four-year, large-scale private sector funded, public service ICT-enabled COPC intervention with rural and remote mining communities. Like all South African communities, apart from large mining house employees and some contractors, most people use available public healthcare services and private traditional as well as limited allopathic private sector providers. In addition to the limitations of facility centred primary healthcare and a fragmented health care system, the many negative health effects of mining on the communities, go unattended.MethodsThis is a rapid, qualitative pragmatic study. Using site and participation convenience sampling, 37 semi-structured individual or group interviews were conducted with 57 stakeholders from 38 of the 135 intervention PHC facilities. Using a data driven, inductive approach, the results were analysed thematically in terms of perceived changes in the role and place of CHWs.ResultsCHWs registered 42 490 households and captured the demographic and social profiles as well as the health status of over 154 910 individuals using AitaHealth™. These data provided healthcare professionals and managers with knowledge about community demographics, at-risk groups and vulnerable individuals. The intervention changed the locational focus of CHW practice and expanded their scope of work and competencies in household comprehensive health education, advice and care. It led to a growth in community and professional confidence in CHWs as trusted members of mining community PHC teams and to more focused and efficient clinic work.ConclusionThis ICT-enabled COPC intervention adopted a comprehensive approach to healthcare delivery that started by including CHWs in PHC teams and locating them in communities. Inclusive and systematic continuous learning, clinically-led CHW service support and ICT-enabled information technology engendered trust in CHWs as competent PHC members, and grew community confidence in them and the PHC system as a whole. Although health, care and other professionals and workers valued the changes the intervention brought to their work as well as people’s lives in underserved and vulnerable mining communities, its sustainability is contingent on the vagaries of political will and financial commitment.

Standards‐based evaluation inform ecological restoration outcomes for a major mining activity in a global biodiversity hotspot

The International Principles and Standars for the Ecological Restoration and Recovery of Mine Sites were used to assess the restoration quality of one of the world's largest mines, located in the world's most biodiverse temperate forest. Quantitative analysis of longitudinal data spanning 35 years scored restoration quality at 2‐stars against a 5‐star forest ecosystem restoration target, with little indication of improvements from adaptive management. Two‐thirds of indicator plants were significantly under‐represented in early‐stage restoration and declined with age. Most plant species were effectively absent, including key structural species. Invasive plants and native legumes were persistently overabundant. Time required for the maturation of tree species will prevent the production of fundamental ecosystem features for well over a century (e.g. hollows and fallen logs), inhibiting functional fauna return (reptiles, bats, and conservation priority cockatoos in particular). The significantly different outcome compared with previous assessments is due to the age of restoration assessed and previous assumptions that early‐stage success indicate that restoration is on the correct, prolonged trajectory toward full ecological restoration. However, previous assessment methods did not consider many key metrics of the standards, nor accurately predict future restoration trajectory. In particluar, initial plant species richness (the only measure of biodiversity in the company's restoration completion criteria) did not reflect future restoration quality. These substandard restoration outcomes may result from removing the deep, multi‐layered bauxitic substrate on which the ecosystem evolved and establishing restoration on shallow topsoil over a more homogenized, impervious substrate. This study demonstrates the value of a robust, adaptable multi‐factor framework and methodology to evaluate restoration outcomes.

Evaluation of road roughness and its influence on operating parameters in open-pit mines

Hauling ore and waste rock is a major cost factor in open-pit mines, encompassing both road maintenance and off-road truck operation. Road maintenance costs are directly influenced by traffic volume and the size of trucks using the roads. Off-road truck operating costs are impacted by various factors, including those affecting their movement, such as the direct interaction between tires and the road surface. Tire-road interaction significantly affects rolling resistance. Rougher surfaces with deeper grooves caused by track sinks lead to higher rolling resistance. This study employed laser profiling to characterize the surface roughness of five mine haul roads in two large Brazilian iron ore mines. This study evaluated the impact of these road irregularities on various operating parameters for 240-ton off-highway trucks, including rolling resistance, average travel speed, travel time, productivity, and unit transport cost. The results indicate that a 10 cm increase in road surface roughness can lead to a significant increase in rolling resistance (up to 5%), a substantial decrease in average speed (25%), a notable increase in travel time (26%), a decrease in productivity (19%), and a corresponding increase in unit transport cost (21%).

What’s in a landscape? Nature, memory, and tourism in Bitterfeld-Wolfen’s post-mining landscape, East Germany

This paper addresses the transformation of the region around the twin-town Bitterfeld-Wolfen in Eastern Germany from a highly polluted industrial hub into a lakeland idyll and destination for recreation and nature-based tourism. From the perspective of local residents of age, the significance of this transformation was fundamentally shaped by German reunification, in particular by the experience of stigmatisation related to high levels of pollution in Bitterfeld-Wolfen in the context of general bias that devalued East German subjectivities in the course of German reunification. As I detail through both historical and ethnographic research, I show how mine restoration and the clean-up of contaminated sites have subsequently acquired meaning beyond ecological recovery and the improvement of public health. Tied up with the uncertainties and ambivalences of the transformation of East Germany and its integration into a West German entity, I demonstrate how the (im)possibility of restoring a destroyed landscape became inseparable from the postulated need of fundamental recovery of an East German region and its inhabitants from, so-perceived, socialist ruination. Consequently, I argue, the clean-up of contaminated sites and the remediation of a large open-cast mine in (former) East Germany produced not only an idyllic post-mining landscape, but a post-socialist one. Furthermore, as an archive of local history, the restored landscape became a way for elderly people to re-appropriate their past through its transformation into a remarkable present. In tracing this contested history, this paper contributes to landscape-centred analyses of post-socialist transformations in Europe.

Soil moisture evidence of self-restoration in coal mining subsidence area of Shendong Mining area: Cognition based on stable isotopes

The Shendong mining area is the largest coal production base in China. However, the area is dry and water scarce, and the ecological environment is fragile. Large scale mining of shallow and thick coal seam in mining area may affect surface moisture and threaten surface ecological security. In order to understand the change of soil moisture in subsidence area. The evaporation loss rate of undisturbed and subsidence soil in mining area was estimated by using water stable isotope technique. The soil particle size and moisture of undisturbed and subsidence soil were compared. The results showed that the soil particle size did not change significantly in the subsidence area, but the continuity of soil structure changed. The evaporation loss rate of soil in subsidence area is about 15 % lower than that of undisturbed soil, and the soil moisture of soil in subsidence area is about 10 % higher than that of undisturbed soil. Further, the Craig-Gordon model is more accurate than the Rayleigh model in estimating the evaporation loss of soil moisture. Our work showed that the soil structure of coal mining subsidence area becomes much looser and the loose cover formed by the surface soil is the main reason for the reduction of soil moisture evaporation. The significant increase of soil moisture will be beneficial to plant recovery and growth, and lay a water foundation for ecological self-restoration in subsidence area. This study is helpful to understand the influence of coal mining subsidence on soil and surface hydrology in arid and semi-arid areas, and has important significance for optimizing and improving the ecological reclamation model of mining areas in western China.

Distribution of Heavy Metals in the Surrounding Mining Region of Kizhnica in Kosovo

This study investigated the distribution of heavy metals in agricultural soils in the vicinity of three large mining landfills of the Kizhnica mine in the Republic of Kosovo. The mining sector is one of the most important sectors of Kosovo’s economic development, and the Kizhnica mine is one of the most important ore producers in Kosovo. Besides the positive aspects, the development of production also has some negative side effects, such as the generation of industrial waste and the possible contamination of surrounding areas, including agricultural land. Therefore, ten sampling sites were selected in the vicinity of the Kizhnica mine. These sites were characterized and assessed as the most important due to the anthropogenic impact of mineral processing and open-tailing waste deposits in Kizhnica. The concentration of Pb, Zn, Cu, As, Cd, Ni, Mn and Sb in the selected samples was determined using inductively coupled plasma–optical emission spectrometry. The data obtained were used to create geochemical maps and calculate the contamination factor, pollution load index and geoaccumulation index. Cluster analysis, Pearson correlation coefficient and air spatial distribution patterns using the air dispersion model were used to evaluate within the area. The results showed that heavy metal levels are influenced by the anthropogenic nature of pollution, confirming a current ecological threat from mining activities in the region. In order to improve waste management, reduce the hazardous impacts of mining and contribute to the sustainable development of the region, the potential reuse of the deposited waste material in the construction industry is proposed.

The role of auditing culture in sustainable mining practices: A review of Ghana’s mining sector

The study looks at Ghana’s mining industry’s audit culture and green mining practices about their social responsibility to the communities where their mines are located. Results: According to this study, the economic motivations of mines and green mining are inversely related. Even large mining companies incur significant costs associated with their green mining initiatives because they require a different budget each year, which has an impact on their ability to maximize wealth. Conversely, mines with strong green mining initiatives enjoy positive public perception, and vice versa. Ghanaian mines do not have pre- or during-mining strategies; instead, they only have post-social and post-environmental methods. The best method for evaluating mines’ environmental performance in the community in which they operate is, according to this study, social auditing. This is primarily influenced by the mine’s audit culture, but it is also influenced by the auditor’s compliance with audit processes, audit guidelines, and, ultimately, the audit firm’s experience. The analysis confirms that Ghana’s mine environmental performance is appallingly low since local audit firms are not used in favor of foreign auditors who lack experience or empathy for the problems encountered by these mining communities. Last but not least, corporate social responsibility (CSR) is connected to Ghana’s development of green mining, either directly or indirectly. Whether the mine adopts a technocrat, absolutist, or relativist perspective on mining will determine this. The study discovered that, in contrast to the later approach, the first two views generate work in a mechanistic manner with little to no consideration for CSR.

The spatial distribution and source of heavy metals in soil-plant-atmosphere system in a large coal mining area

Due to the lack coupling analysis of heavy metals in soil-plant-atmosphere system, the migration and transformation of heavy metals remains unclear. In this study, 240 surface (0–20 cm) soil samples, 365 plant samples and 168 atmospheric dust samples were collected in a large coal mining area, in which selected heavy metals arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), plumbum (Pb), zinc (Zn) were analyzed, to elucidate the spatial distribution and source of heavy metals and their bioavailability. According to the results of ArcGIS mapping analysis, the distribution patterns of Cd, Cu, Pb, and Zn in the three media are similar, while the distribution characteristics of Cr and Ni are highly consistent. The factors contributing to these spatial distribution characteristics of heavy metals could be associated with human activities and the characteristics of the elements. Compared with the background value, Zn, Cr, Pb in soil, Zn, Cr, Cu in plants and Zn, Pb, Cu in atmospheric dust apparently accumulated. The geological accumulation pollution index (Igeo) shows that there exist mild to moderate levels of Cr and Cd pollution in soil, and mild to moderate levels of Cd, Cr, Pb, and Zn pollution in the air. The evaluation of potential risks of heavy metals showed moderate ecological hazards in soil and strong ecological hazards in atmospheric dust. The sources of heavy metals were assessed using principal component analysis (PCA), land use type, and spatial analysis. Anthropogenic factors are the main sources of heavy metal content. Coal-related industrial processes related to coal, sewage irrigation, the use of agricultural chemicals, and vehicle emissions may be anthropogenic sources of heavy metals.

The synchronic and diachronic evolution of key themes around SDG 4 before and after 2015: From a quantitative analysis of web-downloaded texts

The authoritative ideas of what education should be like under the fourth Sustainable Development Goal (SDG 4) are constructed through discourse among key actors of the “international education community” at large. This article presents the evolution of international education discourse, comparing the periods before and after September 2015. The analysis is presented in two parts. The first part discusses the period before the adoption of SDGs in 2015, during which the agenda was formulated through discourse. The author identifies themes such as cognitive and noncognitive skills, learning outcomes, measurement and indicators. Actors shaping the discourse included mission-driven civil society organisations (CSOs), constituency-based CSOs, technical specialist groups, UN Member States and philanthropic organisations. The second part is based on a large sample text mining using 832 web-downloaded texts published between 2015 and 2022. The list of key themes largely mirrors those identified in the first part, although the relative weight among them has changed over time. The emphasis has shifted from global, structural topics to more local, specific ones, with increased attention on individual learners and their skills and knowledge. It suggests the uprooted nature of global governance, particularly at the time of SDG adoption. The fact that the term “SDGs” has permeated to the household level reflects widening participation in the global discourse on education. The author observes two contrasting perspectives: one discusses education’s contributions to noneducational goals, such as employment, economic growth, achieving sustainability or guaranteeing basic human rights; while another represents traditional educationalism, which tends to equate schooling with the traditional classifications of primary, secondary and higher education.

Study on the Application of Comprehensive Gas Control Technology for Source-Separated Three-Dimensional Gas Extraction in Large Mining Faces.

In order to address the challenges of high gas outburst in both the adjacent layers and the coal seam itself faced by large mining faces, a study on the three-dimensional extraction of gas from different sources at a large mining face was conducted. Based on the research on the instability and failure characteristics of the overlying strata during mining and the gas outburst characteristics at the large mining face, a source-separated three-dimensional gas extraction system was established. A comprehensive gas management model for the large mining face, involving the extraction of gas from different sources, has been proposed. This model is suitable for gas management at large mining faces where there is a high gas emission in the adjacent layers and a complex structure of the coal seam. Through numerical simulations using FLAC3D, the height of the "three zones" of the overlying strata and the range of the floor fracture zone at the large mining face were obtained, providing guidance for the layout of high-level drainage roadway, low-level drainage roadway, and floor drainage roadways. Following the coordinated layout of high-level drainage roadway, inclined high-level drainage roadway, and low-level drainage roadway, the reasonable optimization of gas extraction techniques in the coal seam, and the reasonable arrangement of floor rock predrainage roadways, the methane capture efficiency of the large 15115 mining face reached 87.5%. The methane concentrations at the upper corner and in the return airflow being below 0.8%. The methane concentration extracted from the coal seam boreholes is 2.9 times higher than that from the ordinary mining face after adopting "ordinary boreholes + large-diameter boreholes". This gas management model effectively addresses the gas-related challenges of the large mining face and improves the gas extraction rate, achieving harmonious mining and extraction of coal and methane.