Coal Production Research Articles

Development of an Intelligent Coal Production and Operation Platform Based on a Real-Time Data Warehouse and AI Model

Smart mining solutions currently suffer from inadequate big data support and insufficient AI applications. The main reason for these limitations is the absence of a comprehensive industrial internet cloud platform tailored for the coal industry, which restricts resource integration. This paper presents the development of an innovative platform designed to enhance safety, operational efficiency, and automation in fully mechanized coal mining in China. This platform integrates cloud edge computing, real-time data processing, and AI-driven analytics to improve decision-making and maintenance strategies. Several AI models have been developed for the proactive maintenance of comprehensive mining face equipment, including early warnings for periodic weighting and the detection of common faults such as those in the shearer, hydraulic support, and conveyor. The platform leverages large-scale knowledge graph models and Graph Retrieval-Augmented Generation (GraphRAG) technology to build structured knowledge graphs. This facilitates intelligent Q&A capabilities and precise fault diagnosis, thereby enhancing system responsiveness and improving the accuracy of fault resolution. The practical process of implementing such a platform primarily based on open-source components is summarized in this paper.

The effect of cutting speed on the generation of bituminous coal dust: Experimental and theoretical discussion

To address the issue of an unclear mechanism for dust generation, an experiment was conducted to investigate the dust generation and migration under varying cutting speeds of a single cutting tooth. The findings indicate that coal dust production involves a rapid physical transformation process comprising four stages: coal body deformation, formation of the crushing zone, stress release, and collapse of fractured material. Increasing the cutting speed results in a continuous rise in both the total dust production rate and the respiratory dust rate. At a cutting speed of 10 mm/s, the RF coal sample exhibited a total dust production rate of 32.41 g/t, while the HP coal sample had a total dust production rate of 93.10 g/t. The moisture content of the coal samples exhibited a negative correlation with the total dust production rate, whereas the fixed carbon content and porosity showed a positive correlation with this rate. However, the size of the porosity had no significant impact on the production rates of respirable dust and PM2.5 dust. These research findings enhance the understanding of the dust production mechanism during coal and rock cutting, providing guidance for dust control at the origin.

Evidence of Microbial Activity in Coal Seam Production Water and Hydrochemical Constraints

Evidence of Microbial Activity in Coal Seam Production Water and Hydrochemical Constraints

Comparative Analysis of Domestic Production and Import of Hard Coal in Poland: Conclusions for Energy Policy and Competitiveness

In many energy policies, including Poland’s, environmental priorities clash with the issue of energy security. With these contradictions in mind, the main objective of the article is a comparative analysis of domestic production and imports of hard coal in Poland and the formulation of conclusions for energy policy and competitiveness. The analysis covers the years 2018–2023 and concerns three issues: the volume and directions of coal imports to Poland, the qualitative and price competitiveness of coal, and the possibility of substituting imported coal with domestic coal. The research used statistical analysis. Indicators of structure and dynamics as well as comparative analysis were also used. The analysis shows that the structure of coal importers to Poland is quite diverse and includes many geographic directions. However, until 2021, it was dominated by Russia, followed by Colombia, indicating a fairly homogeneous supply market and a continuing tendency to depend on a single importer. Analysis of qualitative competitiveness confirms the existence of balance and industrial resources whose quality parameters (sulfur content, ash content, and calorific value) are comparable to and better than those of imported coal. Polish hard coal can also compete with imported coal in terms of price. From 2021 to 2023, it was clearly cheaper than foreign coal. In the above circumstances, it is quite difficult to unequivocally assess the reasons for importing coal to Poland and to justify dependence on external suppliers. This is especially relevant since domestic mining in 2020–2023 remains stable (periodically even increasing), which does not indicate a decisive shift away from coal as an energy resource.

Do policies make a difference? Assessing the impact of China's air pollution prevention and control action plan on carbon emissions

This study aims to balance the dual objectives of improving environmental quality and achieving carbon peaking and carbon neutrality goals. Utilizing panel data from 274 Chinese cities between 2006 and 2020, this paper employs the difference-in-differences method to examine the impact of the Air Pollution Prevention and Control Action Plan (APPCAP) on urban carbon emissions. Empirical results indicate that the impact of the APPCAP on regional carbon emissions follows an inverted U-shaped curve, exhibiting a dual impact path. Although the implementation of the APPCAP increased the annual carbon emissions of the city by an average of 1.637 million tons, it showed a trend of inhibiting the growth of carbon emissions, although it was not significant. Specifically, the APPCAP is most effective in reducing carbon emissions during the "source prevention" stage, primarily by increasing industrial electricity consumption and reducing coal production and consumption. However, a rebound effect occurs at the policy period's end, with compensatory increases in crude oil and electricity consumption, thereby elevating regional carbon emission levels. The APPCAP's effect on carbon emissions is more pronounced in areas with lower population density and higher environmental regulation intensity. It notably raises carbon emission levels in non-industrial base and non-resource-based cities compared to other cities. Furthermore, the APPCAP positively impacts regional carbon emission intensity and economic growth, significantly driving the secondary industry while minimally affecting the primary industry.

Beneficiation of High Sulfur Tertiary Coal of Assam with Burkholderia sp. GR 8-02. An Eco-Friendly Approach Toward Clean Coal Production

The high sulfur content in North-East Indian coal is one of the primary challenges with using it as an energy source. Therefore, the present study uses Burkholderia sp. GR 8-02 to explore coal beneficiation from the Tipong mine (T20 and T60) in Assam (North-East India). Various particle size fractions (−125 to +210 µm, −210 to +250 µm, −250 to +297 µm, −297 to +400 µm and −400 to +500 µm) were treated and subjected to petrographic and chemical analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), Thermogravimetric analysis (TGA), and Raman spectral analysis. The results revealed a 39.04% and 32.43% reduction in total sulfur for T20 and T60 samples, respectively. The ash content decreased by 19.79% in the T20 coal sample and by 24.52% in the T60 coal samples, with a relative decrease in the mineral matter content of approximately 17.43%. Following beneficiation with Burkholderia sp. GR 8-02, the −125 to +250 µm coal fraction exhibited maximum ash removal. The T20 sample useful heating value increased from 8116 to 8203 kcal/kg and the T60 sample from 8060 to 8210 kcal/kg. X-ray diffraction and FTIR patterns showed mineral phases like quartz, kaolinite, and pyrite. The FTIR spectra indicated altered C-S, SO2, and C=O bonds. The thermal profile showed a 12.54% mass loss difference between untreated and treated coal samples, suggesting lower thermal stability post-treatment without affecting the useful heating value (UHV). The treated coal’s surface leaching and morphological structure changes were investigated using Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS) images. Raman analysis revealed increased carbon crystallinity and molecular structure in treated coal. This study offers an environmentally friendly and efficient approach to clean coal production.

Comparison and selection of flotation processes for the separation of fine and difficult-to-float coal particles

ABSTRACT This work compares the performance of two coal preparation plants (CPPs) with similar flotation feeds to study the compatibility between flotation process and coal slime properties and to guide the design of flotation process and equipment selection. The two plants process coal slimes using “flotation column + flotation machine” and “flotation machine + flotation machine” flowsheet, respectively. The migration rules of different size and density fractions in the flotation were experimentally studied. The operation performance between the two flotation processes was comprehensively compared. The results show that, for feedstocks with high concentration of high-ash fine slimes and intergrown particles, the dual flotation processes can effectively reject intergrown particles and high-ash fine slimes, thereby reducing the ash of flotation concentrate to meet quality requirements. In the rougher flotation column, the flotation perfection index of < 0.045 mm size fraction is 55.67%, which is 4.74% higher than that of the rougher flotation machine. In the sorting of cleaner flotation machine, the particles with low density of < 1.3 g/cm3 are collected preferentially. With the extension of the flotation process, the intergrown particles and high-ash fine slimes gradually report to the clean coal products. The flotation recovery of > 0.25 mm size fraction is relatively poorer compared to other fractions. When the feed has high content of high-ash fine slimes, the process of “flotation column + flotation machine” is preferred. When the feed has high content of middle density fraction, the process of “flotation machine + flotation machine” is preferred for dual flotation. The upper limit of feed size should be strictly controlled in flotation.

Guerrilla farms: Practicing food sovereignty in Assam

With the aim to free Assam from the ‘colonial occupation of India’ and reclaim its sovereignty, the guerrillas of the United Liberation Front of Asom (ULFA) had led a self-determination movement in Assam since 1979. Their struggle is grounded upon the extractive nature of the Indian Government to turn Assam into what scholars have called to be a ‘colonial hinterland’ for oil, tea, coal, and forest products. This article is about the farming initiatives of the ULFA guerrillas under ceasefire, to see how their continued engagement with the land expands the everyday notions of sovereignty. For this, we navigate through the pothar (agricultural field), bari (garden), and habi (jungle) which once were symbols of food sovereignty in rural Assam. In this article, we examine how these spaces have transformed under militarization or the market economy, and the activities of the guerrillas towards reclaiming these spaces under ceasefire. Their demand for sovereignty continues to generate questions of self-reliance, sustainability, and growing food for self and the community. This is in contrast to the security concerns of the state that solely frame the self-determination movements in Northeast India.

MINERAL PRODUCTION AND ENVIRONMENTAL POLLUTION IN NIGERIA

This study empirically determined the effect of mineral production on environmental pollution in Nigeria from 1985 to 2022. The research utilised time series data obtained from the Central Bank of Nigeria (CBN) data bulletin and the World Development Indicators (WDI) of the World Bank. The data analysis methodologies utilised include descriptive statistical analysis, ADF Unit Root test, ARDL Bound Co-integration test, and ARDL methodology. The result of the ADF unit root test indicated the presence of a combination of stationary and non-stationary elements. That is a mixture of I(0) and I(1). Furthermore, the ARDL limits co-integration test has shown the presence of a long-term link between the variables. Finally, the ARDL estimation revealed that crude petroleum and natural gas production, likewise mining and quarrying had significant and positive implication on emission of CO2 in both long and short runs. Coal production had positively significant impact on CO2 emission in the long run but positively insignificant impact in the short run. In addition, metal ores positively and insignificantly impacted on CO2 emission in both the long and short runs. The study's results indicated that mineral mining in Nigeria resulted in a rise in environmental contamination. The report proposed that the Nigerian government should thoroughly evaluate and revise current environmental laws and regulations in order to effectively address the environmental consequences of mineral development. This should include establishing clear standards, guidelines, and permits for mining operations, waste management, pollution control, and rehabilitation of mining sites. KEYWORDS: Mineral Production, Environmental Pollution, CO2 Emission

Research on methane Hazard interval prediction method based on hybrid “model-data”driven strategy

Safe mining of coal has an important impact on energy security, while effective control of methane hazard is the key to ensuring safe coal mining. Methane concentration is the main factor determining the hazard of methane in coal mines, and in order to limit the impact of methane on coal mine safety, this study proposes a methane concentration interval prediction method based on a hybrid “model-data” driven idea. Firstly, by analyzing the data and constructing a methane concentration prediction method based on model-driven, which reduces the influence of multicollinearity in the methane concentration series on the prediction effect, and then, in combination with the deep learning technique, a method based on the Wasserstein distance to improve the Informer model is proposed, and finally a hybrid-driven methane concentration interval prediction model is established by introducing the IOWGA operator and the statistical method. After an example analysis of a coal mine in Guizhou Province, China, the hybrid-driven model proposed in this study has better applicability and prediction accuracy in the methane concentration prediction task, which can effectively prevent the occurrence of coal mine accidents and is more in line with the needs of coal mine safety production.

Exploring the catalytic conversion of aromatic model compounds of coal pyrolysis over Ca(OH)2

The distribution of pyrolysis products from aromatic model compounds in coal catalyzed by Ca(OH)2 was investigated at the molecular level. The composition and relative abundance of the pyrolysis products from coal were analyzed using Py-GC/MS. The rapid pyrolysis products of coal at 600 °C consisted of phenols (15.94 %), non-phenolic oxygenated compounds (25.31 %), aliphatics (49.03 %), aromatic compounds (21.74 %), and other compounds (0.03 %). Six representative aromatic model compounds (2-methoxy-4-methylphenol, p-cresol, 2,4-dimethylphenol, o-cresol, guaiacol, and catechol) were selected. The pyrolysis process of model compounds was primarily the cleavage of C-O and C-C bonds, which resulted in the formation of methoxy and methyl radicals. The results revealed that Ca(OH)2 undergoes acid-base reactions with -OH, thereby increasing the stability of the model compounds. Notably, the impact of Ca(OH)2 on the composition and distribution of pyrolysis products was significantly more pronounced in aromatic compounds containing both -OCH3 and -OH compared to those containing solely -OH. The formation pathways of pyrolysis products involving guaiacol and Ca(OH)2 were elucidated through density functional theory (DFT) calculations, demonstrating that Ca(OH)2 could facilitate more free radicals release and the conversion of model compounds. This study contributes to the understanding of the transformation of aromatic compounds during coal pyrolysis at the molecular level.

Optimization of key link parameters and mechanism of the jet-stirring synergistic column flotation method

In recent years, with the deepening of the degree of coal mining and the improvement of the mechanization and intelligent level of coal dressing, the proportion of fine and micro-fine coal production has been increasing. Micro-fine grade separation has gradually become an important research direction in coal washing industry. This paper is based on a novel jet-stirring synergistic column flotation method, which integrates jet-impact mixing, impeller mixing, and dispersion into the structure of a column flotation tank. By combining with existing research foundations, we construct a corresponding physical model and conduct optimization studies on key parameters related to jetting, impeller mixing, and mechanism. The resulting fundamental theory provides clear insights for the engineering application of this innovative flotation technology. The effects of jet-stirring synergy on bubble adsorption and reagent adsorption were studied, and the flotation effect of the new flotation technology was experimentally verified, laying a theoretical foundation for the industrial application of the device.

Heavy metal migration and enrichment in desulfurization wastewater during low-temperature triple effect evaporation process

Zero discharge of desulfurization wastewater from coal-fired power plants has become important. Desulfurization wastewater and gypsum from different stages of the low-temperature triple-effect evaporation process of a coal-fired power plant were collected and investigated. The results showed that after low-temperature triple-effect evaporation, the concentrations of Na+, Mg2+, K+, and Cl− in the desulfurization wastewater increased by 7.91, 7.15, 8.49, and 8.35 times, respectively. With the progress of low-temperature triple effect evaporation process, the concentrations of As, Cd, Co, Cr, Cu, Mn, Se, and Zn in the wastewater after the triple effects were 5.85, 75.44, 1.28, 2.34, 13.66, 5.58, 8.59, and 4.35 times higher than those in the raw wastewater. Mn and Se exceeded the emission limits by 40 and 10 times, respectively. After triple-effect evaporation, the concentrations of As, Cd, Co, Cr, Cu, Pb, Se, and Zn in gypsum decreased to 46%, 26%, 66%, 41%, 35%, 97%, 39%, and 51% of the raw gypsum, respectively. Compared with that of other metal sulfates, the solubility of PbSO4 was extremely low under low-temperature conditions, and some PbSO4 precipitated during the triple-effect evaporation process, leading to a gradual decrease in the Pb concentration in the liquid phase. The mercury compounds in gypsum after the first and second effects were the same as those in raw gypsum, both of which were HgS and HgO. After third effect, the mercury compound in gypsum also included HgSO4. In addition, owing to the promoting effect of the pH of desulfurization wastewater approaching 5.50 on the generation of HgS, the proportion of HgS gradually increased, and the proportion of HgO gradually decreased from the raw gypsum to the third effect gypsum. Therefore, the stability of the mercury compounds in gypsum was enhanced. It can provide a good reference for the migration and enrichment of heavy metals in the low-temperature triple-effect evaporation process, which is beneficial for the clean production and efficient utilization of coal.

Insight into evolution characteristics of pyrolysis products of HLH and HL coal with Py-VUVPI-MS and DFT

To achieve a comprehensive understanding of the influence of chemical structure on the evolution characteristics of coal pyrolysis products, pyrolysis reaction of two kinds of low rank coal (Huolinhe and Huangling coal) were investigated with pyrolysis-vacuum ultraviolet photoionization mass spectrometry (Py-VUVPI-MS). The soft ionized mass spectral detection can provide evolved information of original pyrolysis product. The chemical structure of coal samples was characterized by solid-state 13C-NMR, indicating HLH coal with more branched chain and longer aliphatic chain structure. The bond dissociation enthalpies (BDE) of β-Cal-Cal and β-Cal-O within model compounds were obtained with density functional theory. The difference of peak temperature with maximum evolution was collected to investigate the effect of the chemical environment on evolution behavior of pyrolysis products. The results reveal that branched and long aliphatic side-chains can reduces BDE of β-Cal-Cal and β-Cal-O, resulting in the lower peak temperature of pyrolysis products derived from HLH coal. Substituent groups (such as alkyl and hydroxyl groups) attached on the aromatic rings can reduce peak temperatures. Moreover, the effects of the different substituted position on the aromatic ring of the methyl group presented on differences of the BDE. An increase in aromatic ring size correlates with a certain degree of reduction in BDE for β-Cal-Cal; consequently, peak temperature of pyrolysis products with larger aromatic rings is lower. The pyrolysis behavior of coal were discussed based on the experimental observations and theoretical calculation, which are beneficial to understand the reaction route and mechanism of coal pyrolysis.

Analysis of the co-hydrogenation process of coal tar and kitchen waste oil based on reaction kinetics model

Kitchen waste oil (KWO) and coal tar (CT) are two commonly used alternatives to crude oil for fuel production through hydrogenation. If these two raw materials can be co-hydrogenated, it will help broaden the company's sources of raw materials. Therefore, in order to reveal the positive and negative impacts of the co-hydrogenation process of these two materials and to conduct a quantitative analysis of these phenomena, co-hydrogenation experiments of CT and KWO were completed in this study. The reaction kinetics parameters of the co-hydrogenation reaction were calculated. Experiments have shown that co-hydrogenation with coal tar hydrogenation products (CTHP) can increase the hydrogenation efficiency of KWO by approximately 1.5%. This promoting effect is mainly attributed to the hydrogen-supplying properties of compounds such as tetralin and hexahydro naphthalene present in the CTHP. Through a combined model of reaction kinetics and thermodynamics, it is calculated that the activation energy of KWO hydrodeoxygenation under the action of catalysts is 50.936kJ·mol-1, while under the action of CTHP hydrogen supply, it is 148.429kJ·mol-1, and this promoting effect accounts for 19.3% of the total reaction (as deduced from comparing reaction rate constants). The experimental data presented in this paper and the calculated reaction parameters can provide a basis for design improvements in technology.

Patterns of spatiotemporal variations in the hydrochemistry and controlling factors of bedrock aquifers in the northern region of the Linhuan mining area

Systematically studying the hydrochemical evolution of bedrock groundwater in mining areas during mining process is crucial for effective groundwater resource management and coal mine production. The spatiotemporal characteristics and hydrochemical evolution patterns of the Permian fractured sandstone aquifer (PA) and the Carboniferous Taiyuan Formation limestone aquifer (CTA), both of which are directly associated with coal mining in the northern Linhuan mining area, China, were investigated using multivariate statistical analyses, hydrochemical graphical methods, ion ratio analysis, and a conceptual model. 72 groundwater samples, collected before and after mining, were classified into four groups by hierarchical cluster analysis (HCA). Principal component analysis (PCA) and ion ratio analysis indicated that water-rock interactions involve mineral dissolution (carbonates, gypsum, dolomite, silicates), cation exchange, and common ion effects. Hydrochemical evolution is influenced by bedrock paleotopography, aquifer hydraulic conductivity, and mining drainage. Paletopographic differences significantly influence water-rock interactions and spatial variability in hydrochemistry, with ion concentrations in groundwater increasing as paleotopographic elevation decreases. The pattern of hydraulic conductivity reflects the control exerted by variations in aquifer characteristics on mineral dissolution, leading to minor changes in hydrochemical characteristics. Mining activities disrupt the aquifer's reducing environment, resulting in a significant increase in groundwater SO42− concentration. These findings provide insights and a solid theoretical foundation for studying the hydrochemical variations patterns of groundwater and these control mechanisms in the hidden coal fields of North China.

Multi-scale neural network for accurate determination of the ash content of coal flotation concentrate using froth images

Flotation concentrate quality is strongly correlated with its froth. Therefore, froth images can be used to determine coal concentrate quality. Earlier studies on using coal flotation froth images to determine concentrate ash content ignore the multiscale characteristics of the images. This paper proposes a multiscale neural network (MSNet) to tackle this challenge. The MSNet model can process images with a wide range of resolutions and extract the image features from multiple scales for quality prediction. The model is validated using laboratorial and industrial datasets. Results show that the MSNet correlates with the laboratorial and industrial samples with R2 values of 0.9430 and 0.8288, respectively. The accuracy was further improved by transfer learning technique, resulting in R2 values of 0.9572 and 0.8647 for laboratorial and industrial samples, respectively. These results exhibit the good adaptability of the proposed MSNet. They also indicate that our MSNet is promising in real-world applications, promoting cleaner and more efficient coal production

Application and Research of Mine Safety Management Strategy Based on the BP Network Model

Coal mine safety production is undoubtedly the cornerstone of the healthy, table, and sustainable development of China’s coal industry, and it also profoundly affects the effective implementation of the national energy strategy. In this context, exploring the application of network models in coal mine safety management strategies not only has significant practical significance, but also has profound development value. By integrating these factors, we can have a more comprehensive understanding of the causes of coal mine safety accidents and provide a scientific basis for formulating effective preventive measures. By collecting and analyzing various data in real-time during the coal mine production process, we can promptly detect abnormal situations, predict potential safety risks, and take corresponding measures for intervention and prevention. This dynamic monitoring and early warning mechanism can not only improve the safety of coal mine production, but also enhance the efficiency and efficiency of coal mine production. In the analysis process, we particularly focused on the advantages of Back Propagation (BP) neural network models in mine safety evaluation. BP neural network models can handle uncertainty and fuzzy information and have strong learning and adaptive capabilities. By constructing a safety evaluation model based on BP neural networks, we can more accurately evaluate the safety risks in the coal mine production process, providing strong support for formulating more scientific and reasonable safety management strategies.

Adoption Drivers of Digital Platform for Coal Production Planning: an Extended UTAUT Model Using PLS-SEM Analysis

In 2022, the coal production industry encountered unprecedented challenges accompanied by a substantial global commodity price surge. The operational impact of this situation surpasses current technological capabilities of coal companies, particularly in optimizing coal blending scenarios. A pivotal aspect of digital transformation involves integration of new digital platform for production planning. This study employs the Unified Theory of Acceptance and Use of Technology in conjunction with decision theory to identify key factors influencing the platform adoption at a coal mining company. Structured questionnaires were utilized, followed by analysis using the SmartPLS 4.0.9.9 software. Findings reveal that both Performance Expectancy and Effort Expectancy positively influence users’ behavioral intention to adopt digital platform for production planning. Behavioral Intention, in turn, significantly impacts actual usage behavior. Unanticipated situational factors and others' attitudes were found to have negligible mediating effects, while variables such as age and experience showed no moderating influence on the pathways from behavioral intention to usage behavior. Companies are advised to improve digital platform performance through functionalities enhancements and pilot testing to reduce perceived effort and stimulate behavioral intention. Additionally, fostering a positive organizational mindset through routine motivational communications can further stimulate usage behavior.

Development status of coal industries in the worlds major coal-producing countries

The global coal industry has changed significantly in recent years. In this paper we analyse the coal production and consumption, imports and exports, and coal prices in China and other major coal-producing countries during the past four decades. The analysis shows that global coal production and consumption have declined over the last three years, in striking contrast to the continuous growth for most of the past 35 years. Australia, Indonesia, and Russia have become the world's major coal providers, while China, India, and the USA, and Germany are the major coal consumers. The world's, and China's, coal industry can be classified into four stages of development: the stable growth phase, stable phase, rapid growth phase, and high-quality phase. Coal prices rose in the world's four major coal markets in 2016 after four consecutive years of falling prices. The elimination of overcapacity and production-optimizing operations in China could assist in achieving a demand and supply balance.