Mining Environment Research Articles

Study of a Small Robot for Mine Hole Detection

China is rich in coal resources, but complex hydrogeological conditions lead to difficulties in coal mining, including coal mine collapses, roof and water damage, and other accidents that occur frequently, resulting in many casualties and property losses. The use of coal mine hole detection technology to detect and analyze the internal environment of the coal mines in advance helps to reduce safety hazards and prevent coal mine accidents; however, the operation of existing coal mine hole detection technology is cumbersome, difficult to control, and encounters problems due to an insufficient depth of jacking. This paper designs a new type of small robot for mine hole detection. Firstly, we analyzed the function and structural design of the mine hole detection robot, designed a variable diameter function according to the characteristics of narrow and uneven mine holes in coal mines, and analyzed the mechanics of the critical parts using theoretical calculations. Secondly, using three-dimensional modeling software (Solidworks 2019), we established a structural model of the small robot for mine hole detection. After that, we designed a hardware circuit and control program for the robot and emphasized the safety design of the circuit, considering the presence of water and gas inside the coal mine. Finally, to verify the feasibility of the design program, the basic parameters and function tests of the mine hole-detection small robot were carried out. The experimental results show that the developed mine hole-detection small robot can adapt to working hole diameters from 65 mm to 100 mm and has a maximum working power of only 12 W and a maximum crawling speed of 3.96 m/min. The maximum crawling slope reaches 90°, which can meet existing mine hole inspection needs. This research provides theoretical and design guidance for developing mine hole-detection robots with substantial engineering practical reference values.

Evaluation of green mine construction level in Tibet based on entropy method and TOPSIS

Green mine construction is a systematic project involving the whole life cycle of mineral resources exploitation and utilization, representing the overall level of development potential. As an important strategic mineral resources reserve base in China, Tibet is rich in mineral resources. In order to calculate the level of green mine construction in Tibet, we obtained different data sources such as statistical yearbooks and mine construction information through field research and discussion. We establish the EMUCIMH evaluation system, select a total of 20 indexes from seven aspects(ecological mining environment, scientific mining method, efficient resource utilization, standardization of energy conservation and emission reduction, intelligent mine construction, standardization of enterprise management and harmonization of mining community),using the Entropy Weight TOPSIS Method to study the problems existing in the process of green mine construction, expecting to provide some references for government departments to make management decisions and for mining enterprises to improve green mine construction. The results show that among the 11 national green mines in Tibet, the construction status is uneven, and there are large differences in the mining methods, the comprehensive utilization of resources, and the ecological environment of mining areas. In contrast, The difference of standardization of enterprise management, intelligent mine construction and the harmonization of mining community is small. Among the specific indicators, in terms of exhaust emissions, mining community harmony and corporate culture are doing well, while they are relatively poor in terms of environmental management and monitoring, technological innovation, and intelligent mine, which need to be improved. Large and medium-sized mines, especially metal mines, the overall level of green mine construction is high, followed by small and medium-sized metal mines and individual Non-metal large mines, and mines with more historical problems faced more difficulties and challenges.

Edge computing for critical environments: Vision and existing solutions

With the increasing connectivity of critical infrastructures through wireless technologies, the importance of edge computing is increasing manyfolds. Edge computing has become an important phenomenon combining the strengths of distributed computing technologies with those of telecommunication technologies. Therefore, new technological breakthroughs are happening in the realm of edge computing for critical environments, such as the next generation underground and open-pit mining. Since the mining technologies are moving at a faster pace towards digitization leveraging connectivity technologies, edge computing plays a crucial role in bringing computing and connectivity into mines to provide latency- and security-critical services on site. In this article, we study how edge computing fulfills the needs of critical environments, focusing on mining environments, and provides important insight into future research directions.

Consideration on Legal Situation of Mine Ecological Restoration in China

Mine ecological restoration system is the guarantee of restoration practice and management. In the past half century, China's mining geological environment protection and restoration management system and land reclamation system have been established and continuously improved, but the current relevant legal system still has some defects, such as: no special legislation, implementations of ecological restoration settlement mechanism, two-in-one scheme compilation and reporting system, mining geological environment restoration t fund system are not smooth, and the binding force of legal responsibility is insufficient. In view of these problems, the revision of Mineral Resources Law, Regulations on Land Reclamation and Provisions on the Protection of the Geological Environment in Mines has become a practical necessity. In the revision, mine ecological restoration system can be constructed from the aspects of preparation and implementation supervision of mine ecological protection and restoration scheme, management of mine ecological restoration fund, ecological background investigation and monitoring, lifelong responsibility investigation, joint punishment and so on.

Method for the Analysis of Respirable Airborne Particulates on Filter Using the Mineral Liberation Analyser

In recent years, the Mineral Liberation Analyser (MLA) has played a pivotal role in analysing respirable and inhalable ambient air samples collected on filters from both underground coal and metalliferous mines. Leveraging backscattered electron (BSE) image analysis and X-ray mineral identification, the MLA offers automated quantitative mineral characterization. The escalating prevalence and severity of mine dust lung diseases, particularly among young miners, have reignited interest in comprehensively understanding the dust’s characterization, encompassing mineralogy, particle size, and shape. Merely measuring total respirable dust exposure and its duration based on gravimetrically determined weight is no longer deemed sufficient in addressing the evolving landscape of occupational health challenges in mining environments. Since the publication of previous studies, efforts have been dedicated to refining the Mineral Liberation Analyser (MLA) methodology for respirable dust sampling. This refinement, discussed in detail in this paper, encompasses various enhancements, such as the implementation of data checks to identify carbon contamination, backscattered electron (BSE) drift, and the misclassification of X-ray spectra. Additionally, an examination of sampling efficiency led to the exploration of using smaller samples as an alternative to the time-intensive analysis of entire filters. Furthermore, this paper presents a reanalysis of paired filter sample sets previously reported using the Sarver Group Methodology. These samples are subjected to analysis using the Mineral Liberation Analyser, providing a more detailed illustration of the outputs derived from the updated methodology and compared to previously published MLA data.

Results of the testing of an automated control system and the application of natural gas burners

Purpose. Testing an automated control system to improve the accuracy of calculating natural gas costs in coalfields and provide reliable information to suppliers and consumers regarding mutual settlements. Research methods. The conditions of operation of the mine degassing system and the methods of monitoring its operational indicators for effective management of the technical condition of the object in the real conditions of the mine environment are considered. Approaches to continuous monitoring of well parameters using structural modules of the ACS of the DSH have been determined. Findings. The DSH ACS module was implemented in the real conditions of the mine environment, which made it possible to carry out automatic monitoring of the methane-air mixture, measurement and preparation for issuing to the operational personnel the current values of pressure drops on the diaphragms, absolute pressure, temperature and volume flow of gas. Originality. A new method of increasing the accuracy of commercial accounting of natural gas of coal deposits has been developed, which consists in constant monitoring of the technical condition of the degassing system and automated accounting of natural gas based on the «DIYA» measuring complex. The average hourly values of gas mass flow were obtained, as well as the difference between the data of the channel of the operating ASUTP KS and the channel of the "Ergomera"-126.MU controller in the complex with the "DIYA" operator station. Practical implications. A mine experiment was conducted on monitoring and control of mine degassing gas pipelines using innovative technical solutions for the rapid and systematic delivery of information about the parameters of the mine degassing system to the dispatch service. The structure, principle of operation, methodology for calculating the consumption of natural gases and coal field gases were developed, and industrial tests of an experimental sample of the ACS of the DSH were carried out with automatic entry of results into electronic reporting journals.

An Extensive Study and Evaluation of Tribological Properties of Fsw Plates Using Linear Reciprocating Tribometer (LRT)

This study extensively focuses on analyzing the fretting wear characteristics of Aluminum-based hybrid Metal Matrix Composites (MMCs) under dry conditions, essential in understanding materials' tribological properties in mining environments. Aluminum-based MMCs offer improved wear resistance and durability, potentially enhancing mining equipment performance. The investigation targeted Aluminum 7075 alloy-based MMCs, comprising 7% fine greenish Silicon Carbide and 3% chopped E-glass fibers (2-3mm length, 10-14 micrometer diameters). Using traditional stir casting and Friction Stir Welding (FSW) techniques, composite plates meeting ASTM standards were fabricated. FSW parameters like rotation speed and tool feed rate were varied.Analyzing fretting wear on the welded zone, employing different loads through Linear Reciprocating Tribometer (LRT), provided insights into the tribological performance of these Aluminum-based hybrid MMCs. The lightweight and exceptional thermal properties of Aluminum have significantly expanded its use across various industries, enabling partial replacement of ferrous materials, especially in MMCs where Aluminum alloys offer distinct advantages over other materials.This research aids in determining the suitability of these MMCs for demanding mining conditions, where materials endure extreme stress. Understanding their tribological behavior is crucial for potential applications in mining equipment, contributing to longevity and improved performance.

A comparative analysis of the performance of backfill heat exchangers in deep mine geological environments

With the increase of mineral mining depth, the technologies of constructing heat exchanger in stopes to exploit geothermal resources from deep mines have received great attention. The heat extraction capacities of heat exchangers are closely related to the geological environments of deep mines, especially backfill mines. Therefore, a three-dimensional unsteady heat transfer and seepage coupling model of backfill heat exchangers (BFHEs) is created and verified in this work using COMSOL simulation software. Then, the influences of geological environments, involving groundwater seepage, initial temperature and thermal conductivity of surrounding rock etc., on the ability of five BFHEs with the equal buried tube length to extract heat in different configurations are investigated by this model. The findings indicate that groundwater flow can significantly improve the performance of BFHEs. Double-layer tube BFHEs have the best overall performance in the studied seepage velocity range. Only when there is no or little seepage is the performance of single-layer tube BFHEs equivalent to that of double-layer tube BFHEs. The heat extraction capacity of BFHEs is greatly improved under seepage conditions with the increase in the initial temperature of surrounding rock, although the impact is low in the absence of groundwater seepage. The benefit of backfill body's thermal conductivity on BFHEs' ability to transport heat is significantly greater than that of surrounding rock, but the effect becomes smaller as the value increases. Further increasing the thermal conductivity of the backfill body will not considerably increase the heat extraction capability of BFHEs after it reaches 2.5 (W·m−1·K−1). Therefore, if the cost is too high, continued enhancement is not recommended. The findings offer theoretical recommendations for optimizing BFHEs’ setup to better adapt to deep mine geological environments and increase geothermal extraction capability.

Root-associated bacterial microbiome shaped by root selective effects benefits phytostabilization by Athyrium wardii (Hook.)

The root-associated microbiome assembly substantially promotes (hyper)accumulator plant growth and metal accumulation and is influenced by multiple factors, especially host species and environmental stress. Athyrium wardii (Hook.) is a phytostabilizer that grows in lead (Pb)-zinc (Zn) mine tailings and shows high root Pb accumulation. However, there remains little information on the assembly of the root-associated microbiome of A. wardii and its role in phytostabilization. A field study investigated the structural and functional variation in the root-associated bacterial microbiome of Athyrium wardii (Hook.) exposed to different levels of contamination in Pb-Zn mine tailings. The root compartment dominated the variation in the root-associated bacterial microbiome but the levels of contaminants showed less impact. Bacterial co-occurrence was enhanced in the rhizosphere soil and rhizoplane but tended to be much simpler in the endosphere in terms of network complexity and connectivity. This indicates that the microbial community assembly of A. wardii was non-random and shaped by root selective effects. Proteobacteria, Chloroflexi, Actinobacteria, Cyanobacteria, and Acidobacteriota were generally the dominant bacterial phyla. The genera Crossiella and Bradyrhizobium were enriched in the rhizosphere and cyanobacterial genera were enriched in the endosphere, demonstrating substantial advantages to plant survival and adaptation in the harsh mine environment. Functional categories involved in amino acid and carbohydrate metabolism were abundant in the rhizosphere soil, thus contributing to metal solubility and bioavailability in the rhizosphere. Membrane transporters, especially ATP-binding cassette transporters, were enriched in the endosphere, indicating a potential role in metal tolerance and transportation in A. wardii. The study shows substantial variation in the structure and function of microbiomes colonizing different compartments, with the rhizosphere and endophytic microbiota potentially involved in plant metal tolerance and accumulation during phytostabilization.

Mechanical properties under triaxial compression of coal gangue-fly ash cemented backfill after cured at different temperatures

The triaxial mechanical properties of cemented backfill are the key indicators that affect the stability of cemented backfill in underground mining areas, and the high temperature environment in mines has become one of the main factors affecting the mechanical properties of cemented backfill. Understanding the triaxial mechanical properties of cemented backfill in high temperature environments is crucial for the stability of cemented backfill in mining areas. To investigate the effect of temperature on the mechanical characteristics of cemented backfill under triaxial compression, triaxial compression experiments were done on coal gangue-fly ash cemented backfill that had been cured at three temperatures (20 °C, 35 °C, and 50 °C). The deviatoric stress-strain curve of cemented backfill under triaxial compression was produced, its deformation parameters, dilatancy, and failure characteristics were investigated, and a more appropriate strength criteria was proposed. The research results indicate that, peak strength and dilatancy stress of cemented backfill under the same confining pressure decrease first and then increase as the curing temperature increases. The failure patterns of cemented backfill under triaxial compression will exhibit layered splitting failure except tension and shear failure since the curing temperature has increased. By comparing it with several other criteria, the Mogi-Coulomb strength criteria was found to be a good reflection of the failure strength properties of cemented backfill cured at different temperatures under triaxial compression. With curing temperature rises, internal friction angle of cemented backfill steadily lowers, while the cohesion first decreases and subsequently increases. The alteration in cohesion is consistent with the peak strength change rule, illustrating that the primary factor influencing peak strength of cemented backfill is cohesion. This study provides a good theoretical reference value for guiding the design of deep mine filling and optimizing the mixture ratio of cemented backfill.

Highly efficient adiabatic and flame-retardant SiO2 aerogel and its fibrous composite for high-temperature applications within underground chambers

In the present scenario, the underground chambers of deep metal mines are plagued by excessively high temperatures, and the existing adiabatic materials have proven to be inadequate in addressing this challenge. Considering these issues, this study introduces an innovative adiabatic and flame-retardant SiO2 aerogel-based fibrous composite designed specifically for underground applications. The optimal preparation method for SiO2 aerogel preparation was identified through monomer and orthogonal experiments, ultimately achieving a low thermal conductivity coefficient of 0.028 W/(m·K). Subsequently, through integral moulding, a composite material was developed, incorporating the optimal SiO2 aerogel as a precursor along with ceramic fibres. The resulting ceramic fibre/SiO2 aerogel exhibited an increased thermal conductivity coefficient of 0.061 W/(m·K). When subjected to a high-temperature combustion source of approximately 700 °C, the temperature of the upper surface of the sample was maintained at 131.9 °C and its mass loss rate was a mere 1.2%, exhibiting strong adiabatic and flame-retardant capabilities of the composite material. Moreover, the composite material exhibited good hydrophobic, adsorbent, and mechanical properties, making it well-suited for underground chamber applications. The research conducted on SiO2 aerogel and its adiabatic ceramic fibre composite not only holds theoretical significance by guiding the development of improved adiabatic materials but also provides practical engineering solutions for mitigating heat transfer through raw rock and reducing chamber temperatures in underground mining environments.

Advancing occupational health in mining: investigating low-cost sensors suitability for improved coal dust exposure monitoring

Exposure to coal dust in underground coal mines poses significant health risks to workers, including the development of diseases such as coal workers’ pneumoconiosis and silicosis. Current available methods for monitoring coal dust exposure are expensive and time-consuming, necessitating the exploration of alternative approaches. Low-cost light scattering particulate matter sensors offer a promising solution, and its development in recent years has demonstrated some success in air quality monitoring However, its application in sensing coal particles is limited partially due to that the operating condition in a mine is different than the atmosphere. Thus, the objective of this paper is to evaluate the impact of common factors encountered in a mining environment on these sensors. The findings revealed that the Air trek and Gaslab sensors were unsuitable, showing poor correlation with reference monitors. SPS30 was promising for low concentrations (0–1.0 mg m−3), while PMS5003 effectively monitored up to 3.0 mg m−3. Changing sensor orientation reduced accuracy. Higher wind speeds (3 m s−1) improved results. Low-cost sensors performed well with coal dust but poorly with Arizona road dust. This study underscores the imperative for enhancing these sensors, thereby facilitating their potential application to enhance the occupational health of miners.

Current Research Status and Development Trends of Cooling Suits in High-Temperature Mine Environments: A Review

To gain a deeper understanding of the current research status of cooling suits in high-temperature mines, this paper provides separate introductions to vest-type cooling suits and full-body cooling suits. It summarizes the categories of cooling suits based on different cooling media and systematically elucidates the advantages and disadvantages of each type. The paper also analyzes the current application status of cooling suits in mine environments. It suggests that the future research directions for cooling suits in mines include the miniaturization of components, intelligent temperature control, optimization of new phase-change materials, development of cooling fabrics, and research in smart fibers.

Effect of a Simulated Coal Mine Environment on Polyurethane Grouting Material and a Proposed Polyurethane Strengthening Method.

When it comes to grouting in coal mines, polyurethane (PU) is often utilized. However, it is of vital importance to consistently improve the mineral PU, considering the significant amount of environmental deterioration to which it is prone. Laboratory experiments were used to model various coal mine conditions. Additionally, a workable technique for PU strengthening using ultrasonic waves was proposed. Compression tests and scanning electron microscopy (SEM) were used to describe the PU-gangue material's induration characteristics. The results showed that ultrasound has a positive impact on PU's mechanical strength. The final strength of the PU was significantly impacted by the size of the coal gangue particles, the amount of dust, and the amount of water. The induration made of gangue and PU with the same mass but differing particle sizes was noticeably different in its compressive strength. The strengthening mechanism showed that the average size of the rigid foam after the ultrasound treatment was smaller, and the 'honeycomb'-structured space in the inner section was more compact, resulting in the rigid PU foam having a higher compressive strength after ultrasound treatment. Furthermore, the dust content and water content of coal mines need to be controlled within a specific range to ensure the effective use of PU grouting materials.

Genomic insights into the adaptation of Acinetobacter johnsonii RB2-047 to the heavy metal-contaminated subsurface mine environment

The subsurface mine environments characterized by high levels of toxic metals and low nutrient availability represent an extreme threat to bacterial persistence. In recent study, the genomic analysis of the Acinetobacter johnsonii strain RB2-047 isolated from the Rozália Gold Mine in Slovakia was performed. As expected, the studied isolate showed a high level of heavy metal tolerance (minimum inhibitory concentrations were 500 mg/L for copper and nickel, 1,500 mg/L for lead, and 250 mg/L for zinc). The RB2-047 strain also showed noticeable resistance to several antibiotics (ampicillin, kanamycin, chloramphenicol, tetracycline and ciprofloxacin). The genomic composition analysis demonstrated a low number of antibiotic and metal resistance coding genes, but a high occurrence of efflux transporter genes located on the bacterial chromosome. The experimental inhibition of efflux pumps resulted in decreased tolerance to Zn and Ni (but not to Cu and Pb) and to all antibiotics tested. In addition, the H33342 dye-accumulation assay confirmed the high efflux activity in the RB2-047 isolate. These findings showed the important role of efflux pumps in the adaptation of Acinetobacter johsonii strain RB2-047 to metal polluted mine environment as well as in development of multi-antibiotic resistance.

Energy evolution mechanism during rockburst development in structures of surrounding rocks of deep rockburst-prone roadways in coal mines

Influenced by the deep high-stress environment, geological structures, and mining disturbance in coal mines, the frequency of rockburst disasters in roadways is increasing. This research analyzed energy evolution characteristics during rockburst development in the elastic bearing zone and energy conversion in the plastic failure zone. The critical energy criteria for structural instability of roadway surrounding rocks were deduced. Numerical software was also applied to simulate the energy evolution during rockburst development in surrounding rocks of rockburst-prone roadways under conditions of different mining depths and coal pillar widths. The occurrence mechanism of rockburst deep in coal mines was analyzed from the perspective of energy in structures of deep roadway surrounding rock in coal mines. The research results show that the critical energy criteria are closely related to the elastic strain energy stored in deep roadway surrounding rocks and the energy absorbed by support systems. The impact energy in roadways is directly proportional to the square of the stress concentration factor k. Moreover, as the mining depth increases, the location of the peak point of maximum energy density gradually shifts to coal ahead of the working face. The larger the mining depth is, the more significantly the energy density is influenced by advanced abutment pressure of the working face and the wider the affected area is. With the increment of the coal pillar width, the distance from the peak point of energy density to the roadway boundary enlarges abruptly at first and then slowly, and the critical coal pillar width for gentle change in the distance is 30 m. Changes in the peak elastic energy density in coal pillars with the coal pillar width can be divided into four stages: the slow increase stage, abrupt increase stage, abrupt decrease stage, and slow decrease stage. The elastic energy density is distributed asymmetrically in deep roadway surrounding rocks in coal mines. Under the action of structures of roadway surrounding rocks, energy evolution in these structures differs greatly during rockburst development under conditions of different coal pillar widths. This research provides an important theoretical basis for the support of rockburst-prone roadways during deep coal mining.

Repurposing End-of-Life Coal Mines with Business Models Based on Renewable Energy and Circular Economy Technologies

This paper presents a methodology to select the most exciting business models based on renewable energy and circular economy technologies within end-of-life coal mines to help develop a renewable-based energy sector, promote sustainable local economic growth, and maximise the number of green and quality jobs. To achieve this goal, first, a structural analysis was developed to select the technical variables that better identify this complex system. Second, a morphological analysis allowed the construction of the scenario space. Third, a multicriteria assessment was developed to achieve this goal, based on the previously assessed relevant scenarios, considering the European Green Deal policies, technical variables that characterise end-of-life coal mine environments, technology readiness level, the European taxonomy, synergistic potentials, contributions to the circular economy, and sector coupling. Finally, result indicators were selected to analyse the alternative options derived from the justification approach, considering the targets set by the European Green Deal and related taxonomy and the regional policy indicators for the Just Transition Fund. The results show that eco-industrial parks with virtual power plants represent the most appropriate business model choice, according to the scoring given to the different aspects. They may be complemented by a hydrogen production plant, provided that specific economic subventions are obtained to achieve balanced financial results.

Effects of uranium mining on soil bacterial communities and functions in the Qinghai-Tibet plateau

The microecological effects of plateau uranium mining are still unknown. In this study, we used 16S rRNA high-throughput sequencing to analyze the impact of plateau uranium mining on the microbial diversity and community structure of tailings soil, tunnel soil, and soil at different depths in an open pit. The results showed that uranium mining significantly reduced soil microbial community richness and diversity indicators, including Chao1, Pielou evenness, and Shannon index (P < 0.05). Uranium mining activities significantly reduced the abundance of RB41, Vicinamidactaceae, and Nitrospira (P < 0.05). Interestingly, the abundance of Thiobacillus, Sphingomonas, and Sulfuriferula significantly increased in the soil samples from various environments and depths during uranium mining (P < 0.05). Beta diversity analysis found that uranium mining resulted in the differentiation of soil microbial communities. Functional enrichment analysis found that uranium mining resulted in the functional enrichment of DNA binding response regulator, DNA helicase, methyl-accepting chemotaxis protein, and Helicase conserved C-terminal domain, whereas cell wall synthesis, nonspecific serine/threonine protein kinase, RNA polymerase sigma-70 factor, and ATP binding cassette transporter were significantly affected by uranium mining (P < 0.05). In addition, we also found that different uranium mining environments and soil depths enriched diverse microbial populations and functions to cope with the environmental pressures that were elicited by uranium mining, including Gaiella, Gemmatimonas, Lysobacter, Pseudomonas, signal transformation histidine kinase, DNA-directed DNA polymerase, and iron complex outer membrane receptor protein functions (P < 0.05). The results have enhanced our understanding of the impact of uranium mining on plateau soil microecological stability and the mechanism of microbial response to uranium mining activities for the first time and aided us in screening microbial strains that can promote the environmental remediation of uranium mining in plateaus.

Study on the suppression characteristics and mechanism of ABC powder on pulverized coal explosion based on the analysis of thermal decomposition characteristics and reaction kinetics

This study investigates the inhibitory characteristics and mechanisms of ABC powder on coal powder explosion using a combination of experimental, theoretical, and numerical methods. In a 20 L spherical explosion experimental system, coal powder was mixed with ABC powder at various mass concentrations. The microstructure and major functional groups of the explosion products were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The proportions of the major functional groups were determined through peak fitting analysis. The research findings demonstrate that the introduction of 60 wt% ABC powder into the coal sample led to a significant decrease in the maximum explosion pressure, from 0.683 MPa to 0.454 MPa, indicating a remarkable reduction of 33.38%. Moreover, the inclusion of 70 wt% ABC powder exhibited complete suppression of coal dust explosions. Thermal decomposition characteristics of the mixed system were investigated using a thermogravimetric analyzer, and the Coats-Redfern integral method was employed to analyze the pyrolysis experimental data. The results suggest that the optimal reaction kinetics models for the combustion stage of coal powder and the mixed system are F1 and F2, respectively. Adding ABC powder increases the activation energy by 27.35% and slows down the pyrolysis rate by 37.97%. Furthermore, numerical simulations using CHEMKIN software were conducted to study the inhibitory effect of ABC powder on coal powder explosion. The results demonstrate that the addition of ABC powder significantly reduces the content of O·, H·, and OH·radicals, which are responsible for sustaining explosive chain reactions within the explosion system. By incorporating the findings of this investigation, the present study offers a comprehensive explication of the intricate micro-level mechanisms that underlie the inhibitory properties exerted by ABC powder on coal dust explosions. These results contribute novel scientific and theoretical foundations, yielding profound insights into the prevention and mitigation of calamitous coal dust explosion incidents within coal mining environments.

Research on Recognition of Coal and Gangue Based on Laser Speckle Images.

Coal gangue image recognition is a critical technology for achieving automatic separation in coal processing, characterized by its rapid, environmentally friendly, and energy-saving nature. However, the response characteristics of coal and gangue vary greatly under different illuminance conditions, which poses challenges to the stability of feature extraction and recognition, especially when strict illuminance requirements are necessary. This leads to fluctuating coal gangue recognition accuracy in industrial environments. To address these issues and improve the accuracy and stability of image recognition under variable illuminance conditions, we propose a novel coal gangue recognition method based on laser speckle images. Firstly, we studied the inter-class separability and intra-class compactness of the collected laser speckle images of coal and gangue by extracting gray and texture features from the laser speckle images, and analyzed the performance of laser speckle images in representing the differences between coal and gangue minerals. Subsequently, coal gangue recognition was achieved using an SVM classifier based on the extracted features from the laser speckle images. The fusion feature approach achieved a recognition accuracy of 94.4%, providing further evidence of the feasibility of this method. Lastly, we conducted a comparative experiment between natural images and laser speckle images for coal gangue recognition using the same features. The average accuracy of coal gangue laser speckle image recognition under various lighting conditions is 96.7%, with a standard deviation of the recognition accuracy of 1.7%. This significantly surpasses the recognition accuracy obtained from natural coal and gangue images. The results showed that the proposed laser speckle image features can facilitate more stable coal gangue recognition with illumination factors, providing a new, reliable method for achieving accurate classification of coal and gangue in the industrial environment of mines.