Journal articles on the topic 'Small coal mines'
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1
Passmore, D., J. Bennett, M. Radomsky, and L. Saperstein. "Tailored safety training for miners in small Pennsylvania surface coal mines." American Journal of Public Health 80, no. 9 (September 1990): 1134–35. http://dx.doi.org/10.2105/ajph.80.9.1134.
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Deng, Bao Ping, Shuai Liu, Chen Wang, Yao Dong Jiang, and Hong Wei Wang. "Numerical Investigation on Passing through Goaf in Coal Mine Failurezone." Applied Mechanics and Materials 275-277 (January 2013): 1518–24. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.1518.
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Random mining by small coal mines left many destruction districts with a large range in Fenxi mining district. According to incomplete statistics, the destroyed areas by small coal mines amount to nearly one hundred square kilometers and have over three hundred million tons of resource reserves in Xinliu, Xinyu and Xinyang these three fields. Small coal mines tend to use outdated techniques such as replacing mining with advancement, small excavation with large stoping and room pillar mining technique, which have a stoping rate of only 10% to 25%. Some of the wellheads were not closed seamlessly, which resulted in self-combustion; some were damaged due to the mining of the lower coal seam. A serious security risk existed during the mining of the lower coal seam due to the uncertainty of gas, water and roof pressure. In addition, the destructed area by small coal mines is badly large in Shanxi Province and even the whole country which remains a huge amount of resources. The implementation of this subject is significant.
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Redondo Vega, José María. "Notas sobre la estructura de la propiedad en la minería de carbón leonesa." Estudios humanísticos. Geografía, historia y arte, no. 10 (February 9, 2021): 57. http://dx.doi.org/10.18002/ehgha.v0i10.6697.
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<p>The structure of the property in Leon's coal mining is based on the existence of smalle mines, a fact that makes the mining space a very fragmented one.</p><p>This charasteristic, which is a historial fact in the beginning of the coal mining, has developed slowly theroughout the last decades towards a concentration of the properties, with a small number of owners.</p><p>The concentration process is very impotant in the hard coal mines, and much less visible in the anthracite ones, where we still find an important number of reduced extension mines belonging to small owners.</p>
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Tkach, Sergye, Natalya Batugina, and Vladimir Gavrilov. "Technological, economic and social aspects of the provision of solid fuels to the Arctic regions of Yakutia." E3S Web of Conferences 192 (2020): 03001. http://dx.doi.org/10.1051/e3sconf/202019203001.
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The article examines the reasons leading to the increase in the price of fuel and energy resources consumed in the Arctic regions of the Yakutia. The paper studies the conditions for the development of coal deposits in the region. It is shown the lack of open cast mines that meet modern criteria for efficient use of small-scale open mining by quality and logistic accessibility. This article determines that with the minimum level of clogging of the hard coal mined and the stabilization of its quality over time, it is possible to efficiently recycle the fuel without other precombustion measures. In the case of development of brown coal deposits, additional enrichment is required after extraction to improve the level of consumables. The paper stresses that development of local small-scale deposits of coal is important direction to improve energetic safety of arctic regions. It is necessary to select the coal mines most suitable for open-cast mining, as close to consumers and also with the best quality indicators. The use of the specified measures of technological and economic management, administrative regulation and improvement of mechanisms of «northern delivery» make it possible to facilitate the creation and operation of new coal mines in the Arctic zone of Yakutia. In turn, this reduce coal delivery periods, its quantity and quality losses in the supply chain, and improve local fuel and energy complexes.
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Yang, Ming Qiang, and De Xi Song. "Exploration on Prevention Methods of Flooding Accidents Caused by Goaf Water in Small Coal Mine Groups." Advanced Materials Research 347-353 (October 2011): 258–63. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.258.
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This paper summarizes the working experiences in prevention and treatment of flooding accidents caused by goaf water in Zhangcun Coal Mine, Pingdingshan Ruiping Company, and puts forward a number of scientific, practical and effective methods for it, including “inspection”, “exploration”, “dredging”, “drainage”, “prevention”, “hiding” and “management” . In addition, the methods discussed in this paper have great significance for safety production in coal mines and helps to improve the recovery rate of shallow coal bed in area where small coal mines concentrate.
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Qiao, Guichuan, Song Du, Wei Liu, Zihao Luo, and Zishen mou. "Development and prospect of environmental treatment and ecological restoration of closed coal mines." E3S Web of Conferences 233 (2021): 01147. http://dx.doi.org/10.1051/e3sconf/202123301147.
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The exploitation of coal mine resources has greatly contributed to China’s economic development, but it has also caused damage to the surrounding ecological environment. With the adjustment and optimization of the national energy structure, many small or unqualified mines have been closed in recent years. Thus, the environmental treatment and ecological restoration of these closed coal mines need to be carried out urgently. In this study, the causes of closed coal mines are analyzed from the perspective of macro policy. Then, the key technical difficulties of comprehensive and systematic restoration and treatment of geological and ecological problems are discussed from multiple perspectives. Finally, the successful restoration and treatment cases of closed coal mines locally and globally are showed. The findings of this study provide ideas and methods for ecological environment restoration and management of closed coal mines.
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Seaton, A. "Coal workers' pneumoconiosis in small underground coal mines in the United States." Occupational and Environmental Medicine 67, no. 6 (June 1, 2010): 364. http://dx.doi.org/10.1136/oem.2009.053934.
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Okalelov, V., and V. Okalelov. "Technological development schemes of small coal mines local reserves." Mining of Mineral Deposits 7, no. 1 (March 30, 2013): 67–73. http://dx.doi.org/10.15407/mining07.01.067.
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Hunting, Katherine L., and James L. Weeks. "Transport injuries in small coal mines: An exploratory analysis." American Journal of Industrial Medicine 23, no. 3 (March 1993): 391–406. http://dx.doi.org/10.1002/ajim.4700230303.
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Kaur, Amarjit. "Hewers and Haulers: A History of Coal Miners and Coal Mining in Malaya." Modern Asian Studies 24, no. 1 (February 1990): 75–113. http://dx.doi.org/10.1017/s0026749x00001177.
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The history of coal mining in Malaya is synonymous with the history of Malayan Collieries and Batu Arang town since coal was only ever economically mined in this small area in Ulu Selangor. The town of Batu Arang, the Malayan Collieries and the mines left an indelible mark on Malayan history. Previous accounts of the history of coal mining are restricted to mentions in general works on labour and the labour unrest of 1936–37 and 1946–47. This paper outlines the role of coal mining in the Malayan economy in the first half of the twentieth century. It also focuses on the history of labour at the collieries and the significant role that labour played in the development and growth of industrial activism in Malaya.
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Zhu, Junqi, Li Yang, Xue Wang, Haotian Zheng, Mengdi Gu, Shanshan Li, and Xin Fang. "Risk Assessment of Deep Coal and Gas Outbursts Based on IQPSO-SVM." International Journal of Environmental Research and Public Health 19, no. 19 (October 8, 2022): 12869. http://dx.doi.org/10.3390/ijerph191912869.
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Coal and gas outbursts seriously threaten the mining safety of deep coal mines. The evaluation of the risk grade of these events can effectively prevent the occurrence of safety accidents in deep coal mines. Characterized as a high-dimensional, nonlinear, and small-sample problem, a risk evaluation method for deep coal and gas outbursts based on an improved quantum particle swarm optimization support vector machine (IQPSO-SVM) was constructed by leveraging the unique advantages of a support vector machine (SVM) in solving small-sample, high-dimension, and nonlinear problems. Improved quantum particle swarm optimization (IQPSO) is used to optimize the penalty and kernel function parameters of SVM, which can solve the optimal local risk and premature convergence problems of particle swarm optimization (PSO) and quantum particle swarm optimization (QPSO) in the training process. The proposed algorithm can also balance the relationship between the global search and local search in the algorithm design to improve the parallelism, stability, robustness, global optimum, and model generalization ability of data fitting. The experimental results prove that, compared with the test results of the standard SVM, particle swarm optimization support vector machine (PSO-SVM), and quantum particle swarm optimization support vector machine (QPSO-SVM) models, IQPSO-SVM significantly improves the risk assessment accuracy of coal and gas outbursts in deep coal mines. Therefore, this study provides a new idea for the prevention of deep coal and gas outburst accidents based on risk prediction and also provides an essential reference for the scientific evaluation of other high-dimensional and nonlinear problems in other fields. This study can also provide a theoretical basis for preventing coal and gas outburst accidents in deep coal mines and help coal mining enterprises improve their safety management ability.
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Kulagina, Liudmila, Tamara Yenutina, and Irina Kirillova. "Increasing the energy efficiency and environmental safety of the operation of smallvolume furnaces by adding a water-fuel mixture and organic components." E3S Web of Conferences 295 (2021): 02002. http://dx.doi.org/10.1051/e3sconf/202129502002.
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Industrialisation is trending manufacturing revolution vector, an urgent task is to increase the energy efficiency and environmental safety of small-volume furnaces processes, which are widely applied in the agricultural industry, asphalt concrete plants, etc. In many countries, there are practically no working coal mines or open-pit mines left. However, in a number of regions, coal waste remained in the form of coal dust, ash or in the form of sludge. Utilization of coal dust by preparation of coal-water fuel (CWF) with subsequent combustion of the mixture is currently being applied as the most suitable method. The article discusses improvement of the technology for the preparation of coal-water fuel by applying the effects of hydrodynamic cavitation and adding waste from the livestock complex.
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Wright, Tim. "The Political Economy of Coal Mine Disasters in China: “Your Rice Bowl or Your Life”." China Quarterly 179 (September 2004): 629–46. http://dx.doi.org/10.1017/s0305741004000517.
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The conditions of industrial workers have been increasingly eroded in post-Mao China. This article examines conditions in coal mining: the industry with the worst health and safety performance in China. After briefly outlining China's record, the article analyses the fundamental causes of the high level of accidents. Despite many regulations on mine safety, governments at all levels have had great difficulty in enforcing the law. Because of the important role of township and village mines in local development, often in areas with few other sources of income, powerful forces work for the survival of many unsafe small mines. Indeed, the safety discourse in China's press partly reflects the interests of the state mines attempting to reduce competition by foisting (higher) safety costs on the small mines. The problem of coal safety will not be solved until China's rural population has other, better and safer, ways to increase family incomes so that they have the option to refuse to risk their lives.
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Meng, Xiu Zhi, Zeng Zhi Zhang, and Zong Sheng Wang. "Study of Real-Time Monitoring System on the Underground Mining Activities Based on Explosion Source Location Technology." Applied Mechanics and Materials 190-191 (July 2012): 1179–82. http://dx.doi.org/10.4028/www.scientific.net/amm.190-191.1179.
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The mining boundary ultra-layer & cross-border of some small coal mines in the profit-driven results in a many of safety accidents, waste of resources and environmental damage while the state can not achieve the full uninterrupted supervision because of the backward monitoring tools and equipment. In this situation the real-time monitoring system for underground mining activities is designed based on explosion source location technology. Small and medium-sized coal mines tunnel by blasting operations. The P waves are picked up by acceleration vibration sensors buried underground that are identified and dealt by using wavelet transform. The bursting point is located by the Geiger algorithm and displayed in the mine’s electronic map. The monitor system has good stability, small positioning error by field-proven.
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Rehman, Zahid Ur, Saira Sherin, Sajjad Husain, Noor Muhammad, and Talat Bilal. "Assessment and Quantification of Risks Associated with Small Scale Mining, Khyber Pakhtunkhwa, Pakistan." International Journal of Economic and Environmental Geology 11, no. 3 (December 4, 2020): 65–69. http://dx.doi.org/10.46660/ijeeg.vol11.iss3.2020.478.
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Small scale mining industry is considered more hazardous than other industries worldwide. Large number of workers receive minor and major injuries leading to disabilities or loss of lives due to frequent accidents in mines. Main causes of accidents in mines are fall of roof, improper ventilation system, gases, fires and mine explosions. Beside these hazards, violation of rules and regulations for mine workers are common, which also cause accidents. This paper is focused on issues associated with the health and safety of workers of Cherat Coal Mines (CCM), Abbottabad Coal Mine (ACM) and Abbottabad Soapstone Mine (ASM), Pakistan. The collected data were analyzed with SPSS computer statistics software. The data analyses indicated that the lack of education and violation of safety laws cause accidents in mines. Results show that problems that were rated higher by more than 60% of workers included slide and fall, dust, roof fall and explosive related hazards. In survey more than 50% of the workers admitted the existence of gases, fire and low height mines are common hazards in their workplace. The results also indicated that not only workers but management are also affected by accidents. More than 17% of worker in CCM faced serious accidents up to 3 times during one year. Up to 26% of workers in CCM, 13% in ACM and 15% in ASM suffered accidents for which they had 3 workdays off. It has been concluded that training should be arranged, especially the safety related training on regular basis to reduce the risk of accidents.
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Shen, Lei, and Philip Andrews-Speed. "Economic analysis of reform policies for small coal mines in China." Resources Policy 27, no. 4 (December 2001): 247–54. http://dx.doi.org/10.1016/s0301-4207(02)00009-0.
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Schürmann, Thomas. "Conditions for a Successful Farewell." (Post-)Industrial Memories. Oral History and Structural Change 31, no. 2-2018 (October 6, 2020): 22–36. http://dx.doi.org/10.3224/bios.v31i2.03.
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In 2018, when the last German hard coal mines were closed down, the conditions were relatively favourable, especially in the coal region of Ibbenbüren in Northern Westphalia. This district is marked by small towns and medium-sized enterprises with a relatively low unemployment rate. On the one hand, the shutdown without greater lay-offs was enabled by the co-working of the trade union and the mining company. This, on the other hand, depended to a large extent on external influences, not least on state subsidies and the preceding integration of the German hard coal industry into a rescue company. Furthermore, the relatively smooth transition would not have been possible without the willingness of many miners of covering far distances to other locations. This article is based on narrative interviews conducted before the shutdown of 2018 with miners and other persons involved, focusing on their memories of mining in Ibbenbüren.
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Liu, Xuewei, Quansheng Liu, Bin Liu, and Yongshui Kang. "A Modified Bursting Energy Index for Evaluating Coal Burst Proneness and Its Application in Ordos Coalfield, China." Energies 13, no. 7 (April 5, 2020): 1729. http://dx.doi.org/10.3390/en13071729.
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Coal burst is a type of dynamic geological hazard in coal mine. In this study, a modified bursting energy index, which is defined as the ratio of elastic strain energy at the peak strength to the released strain energy density at the post-peak stage, was proposed to evaluate the coal burst proneness. The calculation method for this index was also introduced. Two coal mines (PJ and TJH coal mines) located in Ordos coalfield were used to verify the validity of the proposed method. The tests results indicate that modified bursting energy index increases linearly with increasing uniaxial compressive strength. The parameter A, which is used to fit relation between total input and elastic strain energy density, has a significant effect on the modified bursting energy index. A large value of parameter A means more elastic strain energy before the peak strength while a small value indicates most of input energy was dissipated. Finally, the coal burst proneness of these two coal mines was evaluated with the modified index. The results of modified index are consistent with that of laboratory tests, and more reasonable than that from original bursting energy index because it removed the dissipated strain energy from the total input strain energy density.
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Perov, M. O., and I. Yu Novitsky . "World experience of methane utilization in closed coal mines." Problems of General Energy 2021, no. 4 (December 22, 2021): 30–39. http://dx.doi.org/10.15407/pge2021.04.030.
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The article analyzes the world experience in assessment of the methane emissions from closed mines and the possibilities of its utilization for the country's economy by natural gas producers. Government regulators, the oil and gas sector, the agencies for development and policymakers should consider methane resources by identifying potential hazards associated with the methane release after mine closure and decommissioning and improving the controllability of emission reduction measures. Important concomitant benefits of methane from closed mines extraction and utilization are a significant reduction in the risk of uncontrolled surface emissions, the exploitation of gaseous resources that would otherwise become waste, and a reduction in greenhouse gas emissions. According to the researchers, 103 billion m3 of methane was emitted from existing underground and open deposits in 2010, and another 22 billion m3 from closed mines. The total amount of 125 billion m3 for 2010 is 50% higher than the estimate of 83 billion m3 obtained by the Emissions Data System of the American Geophysical Union. This is stated in a new study by the Pacific Northwest National Laboratory of the US Department of Energy. The closure of coal mines and, consequently, methane emissions from closed mines will continue to be a pressing and important issue in the foreseeable future as countries continue to exploit and deplete their coal reserves at an ever-increasing rate. This is the case in many developed countries, where coal production is declining and mines are closing. However, this also applies to some developed and developing countries, where coal mining will continue to play a significant role in the structure of the energy balance, and closed mines will be replaced by new ones. Thus, the total emissions from closed and closed mines can be significant and are likely to be increasingly significant. In 2010, the Ministry of Foreign Affairs accounted for 17% of global emissions of mine methane and, according to forecasts, in 2050 this share may increase to 24%. Coal is paramount in ensuring the energy security of many countries and plays a significant role in mitigating energy shortages around the world. As coal reserves deplete or due to changes in the energy sector of the economy, mines are inevitably closed and decommissioned. Closure of mines can provide a small but important opportunity to use such an environmentally friendly source of energy as methane from closed mines (MSS), which can be extracted and disposed of using existing technologies. There is an urgent need to develop projects that will be implemented after the cessation of mining activities and aimed at reducing overall emissions from the life cycle of coal mining, by optimizing the extraction and utilization of methane that would otherwise enter the atmosphere. World experience and theoretical studies of methane emissions to the surface during conservation (closure) of mines are important for understanding the processes of methane release and the corresponding degree of its further involvement in the economy of Ukraine. Keywords: methane emissions, utilization projects, closed mines, methane flow, potential danger
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Li, Wei Guang, Chao Li, and Ke Li Chen. "Study on Technology of Mechanized Mining in Extremely Thin Coal Seam." Advanced Materials Research 962-965 (June 2014): 980–83. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.980.
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The reserve proportion of thin coal seam in Sichuan Province is as high as 60%, of which the extremely thin coal seam mines with the coal thickness less than 0.6m take up 34.3% in the total number of Sichuan coal mines. Exploiting the extremely thin seam called Xiayuantan in Laoyingyan Coalmine confronts so many problems, such as small working space in coalface, difficulty in transporting, high labor intensity, poor production, and low stoping efficiency. Aiming at these problems, this paper puts forward the conventionally-mechanized coal winning technology, investigates the selection, matching, organization and management of equipment in mechanized mining face. Moreover, it demonstrates the rationality of associated equipment selection, that is, MG100-TP off-pan shearer is suitable for exploiting the extremely thin coal seam mechanically. There are less workers in the mechanized mining face, the raw coal production and the stoping efficiency have been enhanced, the roof condition of workface has been improved,serious injury and any other more serious accidents have been completely eradicated. The technology obtains remarkable economic effects and safety benefits.
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Valiulin, S. V., A. A. Onischuk, A. M. Baklanov, A. A. Bazhina, D. Yu Paleev, V. V. Zamashchikov, A. A. Korzhavin, and S. N. Dubtsov. "Effect of coal mine organic aerosol on the methane/air lower explosive limit." International Journal of Coal Science & Technology 7, no. 4 (March 28, 2020): 778–86. http://dx.doi.org/10.1007/s40789-020-00313-4.
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AbstractOrganic aerosol is formed in coal mines due to heat release and evaporation of organics from coal during the longwall operation. This frictional heating occurs when a metallic cutting bit strikes a rock. Thus formed organic aerosol can contribute significantly to the explosivity of methane/air atmosphere in coal mines. In this paper, the flammable limits for the methane–air mixtures with organic aerosol are determined. For this purpose, organic aerosol is synthesizes from the coal-tar pitch in a laboratory evaporation–nucleation flow chamber. Aerosol particles synthesized under laboratory conditions are aggregates consisting of small primary particles with the fractal-like dimension Df = 2.0 ± 0.1, which is close to Df = 2.1 ± 0.1 of coal mine aerosol. It is shown that the flammability of organic aerosol/methane mixture in air is in good agreement with the Le Chatelier additive principle. The lower ignition limit for the pure organic aerosol in air is 44 g/m3.
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Wang, Chao, Cheng Liang Zhang, and Lei Liu. "Analysis on Coal Mine Safety Status in China and its Countermeasures." Applied Mechanics and Materials 448-453 (October 2013): 3814–17. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.3814.
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Aiming at actual situation of coal mine safety in China, the main problems in coal mine including geological conditions, scientific support and safety investment, shortage of technicians, safety training and education, and supervision laws were respectively analyzed, and the preventive countermeasures such as strengthening research of mechanism and prevention method of coal mine accidents, increasing safety investment, improving safety training and education, closing or integrating unqualified small coal mines, strengthening safety production supervision and perfecting legal system should be adopted to improve safety status of China coal industry.
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Hall, Noemi B., David J. Blackley, Cara N. Halldin, and A. Scott Laney. "Continued increase in prevalence of r-type opacities among underground coal miners in the USA." Occupational and Environmental Medicine 76, no. 7 (April 25, 2019): 479–81. http://dx.doi.org/10.1136/oemed-2019-105691.
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IntroductionRespirable crystalline silica exposure has been implicated in the resurgence of coal workers’ pneumoconiosis (CWP) in the USA. A 2010 report found an increasing prevalence of r-type opacities, which are associated with silicosis lung pathology, on the radiographs of working underground coal miners in central Appalachia. This analysis updates that report by assessing the prevalence of r-type opacities during 2010–2018 compared with earlier decades.MethodsData from the Coal Workers’ Health Surveillance Program were used to calculate the prevalence of r-type opacities on radiographs of working underground coal miners. The data were restricted to radiographs taken during 1 January 1980 to 15 September 2018. The presence of r-type opacities was defined as an r-type classification for either the primary or secondary shape/size of small opacities. Prevalence ratios for r-type opacities were calculated using log binomial regression.ResultsRadiograph classifications for 106 506 miners were included in analysis. For the USA overall, the prevalence of r-type opacities among miners with radiographs taken during 2010–2018 compared with 1980–1989 has increased (PR 2.4; 95% CI 1.9 to 3.0). For central Appalachia, the proportion of r-type opacities observed increased when comparing 1980–1989 to 2010–2018 (PR 6.0; 95% CI 4.6 to 7.9).ConclusionsThe prevalence of r-type opacities on the radiographs of Appalachian underground coal miners continues to increase, implicating exposure to crystalline silica in respirable coal mine dust. The current findings underscore the importance of monitoring and controlling exposure to silica in coal mines.
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Yan, Guangwei, and Dandan Feng. "Escape-Route Planning of Underground Coal Mine Based on Improved Ant Algorithm." Mathematical Problems in Engineering 2013 (2013): 1–14. http://dx.doi.org/10.1155/2013/687969.
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When a mine disaster occurs, to lessen disaster losses and improve survival chances of the trapped miners, good escape routes need to be found and used. Based on the improved ant algorithm, we proposed a new escape-route planning method of underground mines. At first, six factors which influence escape difficulty are evaluated and a weight calculation model is built to form a weighted graph of the underground tunnels. Then an improved ant algorithm is designed and used to find good escape routes. We proposed a tunnel network zoning method to improve the searching efficiency of the ant algorithm. We use max-min ant system method to optimize the meeting strategy of ants and improve the performance of the ant algorithm. In addition, when a small part of the mine tunnel network changes, the system may fix the optimal routes and avoid starting a new processing procedure. Experiments show that the proposed method can find good escape routes efficiently and can be used in the escape-route planning of large and medium underground coal mines.
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Tai, Yang, Guozhi Lu, Hongchun Xia, Wenyang Zhang, Hongjie Liu, and Yanqun Zhang. "Position optimisation for a roadway under small coal mines in same coal seam: a case study." Journal of Geophysics and Engineering 17, no. 5 (July 15, 2020): 870–82. http://dx.doi.org/10.1093/jge/gxaa036.
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Abstract According to the failure law of the 1070 main roadway, this paper proposes a reasonable position for large section roadways under small coal mines and a design for seven roadway positions. RS2 software was used to establish a numerical model to select a reasonable position for the roadway. The influences of roadway positions on roof separation amount, roof subsidence, lateral displacement on the ribs, vertical stress on ribs and roadway failure areas were revealed. On the basis of influence laws, reasonable positions for the roadway could be determined. In this study, a center distance of 5 m was deemed a reasonable position. Finally, an industrial test was conducted at the original roadway. The experimental results indicate that the deformation of the roadway could be well controlled and the roadway position is reasonable.
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Weeks, J., D. Swedler, K. Pollack, and J. Agnew. "RISK FACTORS FOR FATALITIES IN SMALL UNDERGROUND COAL MINES IN THE U.S." Injury Prevention 18, Suppl 1 (October 2012): A35.3—A35. http://dx.doi.org/10.1136/injuryprev-2012-040580a.41.
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Zheng, Liping, Lin Zhu, Wei Wang, Lin Guo, and Beibei Chen. "Land Subsidence Related to Coal Mining in China Revealed by L-Band InSAR Analysis." International Journal of Environmental Research and Public Health 17, no. 4 (February 12, 2020): 1170. http://dx.doi.org/10.3390/ijerph17041170.
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Geological disasters, including ground deformation, fractures and collapse, are serious problems in coal mining regions, which have threatened the sustainable development for local industry. The Ordos Basin is most known for its abundant coal resources. Over-mining the underground coal resources had induced land deformation. Detecting the evolution of the land deformation features and identifying the potential risk are important for decision-makers to prevent geological disasters. We analyzed land subsidence induced by coal mining in a 200 km 2 area in the Ordos Basin for the time period 2006–2015. ALOS-1 PALSAR images from December 2006 to January 2011 and ALOS-2 PALSAR-2 images from December 2014 to July 2015, optical remotely sensed images and coal mining information were collected. The small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) method and differential interferometric synthetic aperture radar (D-InSAR) method, GIS and statistical analysis were adopted. Results show that the maximum subsidence rate and cumulative subsidence along the line of sight (LOS) were −65 mm/year and −246 mm, respectively, from December 2006 to January 2011. The maximum cumulative subsidence was −226 mm from December 2014 to July 2015. The new boundary of the mining goafs from 2014 to 2015 and the most dangerous risk region were mapped. Moreover, the effect of large-scale mining coal, with the production volume exceeds 1.2 million tons per year, with the operation time more than 20 years on land subsidence was found greater than small and medium-scale coal mines and reached −59 mm/year. The recently established small-sized and medium-sized coal mines show high land subsidence. This study will contribute to better understand the land subsidence process in mining region and provide scientific support for government to prevent land subsidence.
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Yin, Zhiqiang, Zhiyu Chen, Jucai Chang, Zuxiang Hu, Haifeng Ma, and Ruimin Feng. "Crack Initiation Characteristics of Gas-Containing Coal under Gas Pressures." Geofluids 2019 (February 7, 2019): 1–12. http://dx.doi.org/10.1155/2019/5387907.
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In deep coal mines, coal before the working face is subjected to coupled high mining-induced stress and gas pressure. Such condition may facilitate crack formation and propagation in the coal seam, leading to serious coal and gas disasters. In this study, the mechanical properties (i.e., uniaxial compressive strength, tensile strength, and fracture toughness) of gas-containing coal with four levels of initial gas pressure (i.e., 0.0, 0.5, 1.0, and 1.5 MPa) were investigated by uniaxial compression, Brazilian disc, and notched semicircular bending loading test. A newly developed gas-sealing device and an RMT-150 rock mechanics testing machine were used. Fracture modes under different initial gas pressures were also determined. A theoretical method of fracture mechanics was used to analyze crack initiation characteristics under gas adsorption state. Results show that the uniaxial compressive strength, tensile strength, and fracture toughness of gas-containing coal decreased with increasing initial gas pressure. The tensional fracture occurred in gas-containing coal under uniaxial compressive loading with high gas pressure. Cracks in gas-containing coal propagated under small external loads due to the increase in effective stress of crack tip and decrease in cracking strength. This study provided evidence for modifications of the support design of working face in deep coal mines. Furthermore, the correlations between fracture toughness, compressive strength, and tensile strength of gas-containing coal were investigated.
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Chen, Yuan, Lan Fen Niu, and Guo Biao Ren. "Application of Computer Network Technology to Control the Coal Quality." Applied Mechanics and Materials 536-537 (April 2014): 1215–18. http://dx.doi.org/10.4028/www.scientific.net/amm.536-537.1215.
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In recent years, the government has stepped up efforts to control coal mine. A large number of small coal mines were shut down for the simple reason that they are not up to the standards. More and more coal enterprises now put the informatization at the top of the long-term development list. In the management information system, the coal quality control is regarded as a main functional module. The traditional process of coal quality testing can’t meet the regulatory requirements. With information technology, to get faster and more accurate monitoring of coal quality and give management advice are the important content of a coal enterprise information construction. This article presents how to use the computer network technology to better control the coal quality.
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Liu, Jiajia, Jianmin Hu, Mengqi Shen, Ming Yang, and Yingxiang Fang. "LNMR Study on Microstructure Characteristics and Pore Size Distribution of High-Rank Coals with Different Bedding." Advances in Civil Engineering 2021 (October 7, 2021): 1–8. http://dx.doi.org/10.1155/2021/8542630.
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In order to study the pore structure characteristics of high-rank coals with different bedding, NMR experiments were carried out for high-rank coals with different bedding angles (0°, 30°, 45°, 60°, and 90°). The results show that the distribution of T2 map of high-rank coal with different bedding is similar to some extent, showing a double peak or triple peak distribution, and the first peak accounts for more than 97% of the total, indicating that small holes are developed in high-rank coal with different bedding, while macropores are not developed. The influence of bedding angle on the fracture proportion is less than 0.3%. Compared with the fracture proportion, the effect of bedding angle on the proportion of microhole, medium hole, and large hole is greater and presents a certain rule. There are certain differences in T2 cutoff value (T2C) of high-rank coal with different bedding. The relationship between bedding angle and T2C conforms to exponential function, and the correlation degree R2 is 0.839. The research results provide a theoretical basis for gas extraction and utilization and prevention of gas disaster in coal mines in China.
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Wu, Rui, P. H. S. W. Kulatilake, Hao Luo, and Kui Zhao. "Design of the Key Bearing Layer and Secondary Mining Technology for Previously Mined Areas of Small Coal Mines." Rock Mechanics and Rock Engineering 53, no. 4 (November 16, 2019): 1685–99. http://dx.doi.org/10.1007/s00603-019-02001-5.
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Andrews-Speed, Philip, Guo Ma, Bingjia Shao, and Chenglin Liao. "Economic responses to the closure of small-scale coal mines in Chongqing, China." Resources Policy 30, no. 1 (March 2005): 39–54. http://dx.doi.org/10.1016/j.resourpol.2004.12.002.
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BRYK, Dmytro, Oleg GVOZDEVYCH, Lesya KULCHYTSKA-ZHYHAYLO, and Myroslav PODOLSKYY. "Technogenic carbonaceous objects of the Chervonohrad mining and industrial district and some technical solutions for their using." Geology and Geochemistry of Combustible Minerals 4, no. 181 (December 27, 2019): 45–65. http://dx.doi.org/10.15407/ggcm2019.04.045.
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Ukraine has significant coal resources. Chervonohrad Mining and Industrial District is the main coal complex in the west of Ukraine. In recent years, the average annual coal production in the mines of Chervonohrad Mining and Industrial District has amounted to 1.5 bn t, coal ash varies over a wide range of 25 to 53 %, average coal ash content of about 40 %. Coal mining has produced millions of tons of coal waste every year. Concentration of technogeneous coal objects (mines, mining infrastructure, coal-mining waste dumps and wastes of coal enrichment) in a relatively small area has caused environmental degradation. Therefore, technological and environmental aspects of carbon-containing technogenic objects are particularly important and actual. Coal-waste dumps in the territory of Chervonohrad Mining and Industrial District are characterized in detail. The dumps cover different areas – from 9–10 to 29–30 ha, the height of the dumps reaches 62 m at the mostly heights of 25–40 m. The total waste deposit in the dumps of existing mines has a volume of more than 20 million m3. The coal wastes from Mezhyrichanskaya mine coal-waste dump was investigated to determine the suitability for thermochemical processing. Technical characteristics of taken coal-waster samples is presented. The technogenic carbonaceous objects and the impact to the environment are evaluated. The developed and patented technical and technological solutions for the technogenic carbonaceous objects using are considered. It is shown that the concept of industrial development of coal wastes dumps is based on two aspects – extraction of valuable mineral components and energy utilization of carbonaceous wastes of coal production. Its patented as Patents of Ukraine technological schemes for terrestrial process in of solid carbonaceous raw material from dumps and sludges with the production of coal tar and synthesis gas CO + H2 are presented, as well as the scheme of a system for utilization of heat from coal dump. Recommendations for the implementation of innovative technologies are based on the results of the laboratory research. The purpose of the resolution is to obtain valuable components and energy from coal wasters while improving the environment.
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Lin, Xiaobo, Pingsong Zhang, Fanbin Meng, and Chang Liu. "A Coal Seam Thickness Prediction Model Based on CPSAC and WOA–LS-SVM: A Case Study on the ZJ Mine in the Huainan Coalfield." Energies 15, no. 19 (October 5, 2022): 7324. http://dx.doi.org/10.3390/en15197324.
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The precise prediction of coal seam thickness in operating mines is crucial for the construction of transparent mines. Geological borehole data or a small amount of seismic information is frequently used in traditional coal seam thickness prediction methods; however, these methods have poor precision. In this study, we introduced a model for predicting coal seam thickness based on the comprehensive preference for seismic attribute combination (CPSAC) and the least squares support vector machine (LS-SVM) optimized by the whale optimization algorithm (WOA). We used the CPSAC to modify the mass disturbed data in the seismic attribute data to predict the coal seam thickness. To achieve this the sample size was reduced by optimizing the seismic attribute combinations, and the modified attribute data was entered into the LS-SVM., Furthermore, to create an accurate prediction model for coal thickness, we employed the WOA to determine the optimal penalty coefficient and kernel coefficient of the LS-SVM. An empirical case study was conducted in the northeast mining area of the ZJ mine in the Huainan coalfield. The coal thickness of two mining faces in this research area were estimated and compared, demonstrating the proposed method’s high prediction accuracy. The proposed method has guiding implications for developing an accurate mining geological model and facilitating the accurate use of coal resources.
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Obracaj, Dariusz, Nikodem Szlązak, and Marek Korzec. "Using a Mine Dewatering System to Increase Cooling Capacity and Energy Recovery of Underground Refrigeration Plant: A Case Study." Energies 15, no. 24 (December 14, 2022): 9481. http://dx.doi.org/10.3390/en15249481.
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Heat stress in deep hot mines is a factor that often determines the possibility of technical mining of natural resources. One of the solutions enabling miners to work in such mines is air cooling. Cooling systems vary, and their selection depends on the type of mine and the mining methods used. Limited air cooling capabilities exist in electric-powered coal mines. The main solution for air cooling is based on movable spot air coolers. Such systems commonly use surface or underground refrigeration plants. An underground refrigeration plant (URP) equipped with compressor chillers does not achieve more than 2.5–3.0 MW of cooling capacity due to the limited heat rejection capacity of return air streams in a typical coal mine. The method discussed in this paper, using mine water to discharge waste heat from the underground refrigeration plant, provides a measurable benefit for optimizing the mine air cooling system. The main purpose of this research is to study the feasibility and effect of water diversion from the actual mine drainage system to the underground refrigeration plant. The water drainage system in an underground mine is called the dewatering system of the mine. The heated water in the condensers of the chillers is directed back to the mine’s central dewatering system. The recovery from water discharged to the surface contributes to optimising energy consumption for a mine air cooling and the sustainable discharge of wastewater. In addition, using the total water flow from the mine dewatering system to reject heat in compressor chillers, compared with the traditional solution, can improve the cooling capacity of URP. These findings may provide beneficial guidance for practical applications in deep hot mines with small natural water inflow.
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Li, Jing, Ruixin Zhang, Zequan Li, and Weihong Guo. "Research on the Prediction Method of Monthly Hidden Danger Quantity in Coal Mine Based on BP Neural Network Periodic Combination Model." Mathematical Problems in Engineering 2022 (December 28, 2022): 1–10. http://dx.doi.org/10.1155/2022/7288090.
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To better prevent the occurrence of hidden dangers of coal mine accidents and ensure the safety production of coal mine enterprises. This paper mines and analyses the pattern of historical monthly hidden danger quantity in the coal mine and constructs three models: the traditional backpropagation (BP) neural network model, the BP neural network based on the adaptive moment estimation optimization algorithm (Adam-BP) model, and the BP neural network prediction model with the introduction of monthly moderators (Month-Adam-BP). The experimental results show that the Adam-BP model can improve the prediction accuracy, in which the mean absolute percentage error (MAPE) improves by 8.93%, the root mean square error (RMSE) improves by 8.15%, the postdifference ratio C improves by 0.04, and the small error probability P improves by 0.12; the Month-Adam-BP model with the introduction of the monthly adjustment factor further improves the prediction accuracy, in which MAPE improves by 2.61%, RMSE improves by 5.41%, the postdifference ratio C improves by 0.06, and the small error probability P improves by 0.03. And the Month-Adam-BP model prediction accuracy reaches the level 2 standard with credible prediction effect; it can also be used to predict coal mines with periodic characteristics of hidden hazard data. Our prediction results show that the predicted number of hidden hazards in this coal mine for the next month is 29, which is an increase compared to the number of hidden dangers in the previous month. Thus, the coal mine safety managers need to strengthen the management of hidden hazards further to prevent accidents, which can better serve the standardization of coal mine safety production and ensure the smooth production of the coal mine.
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U, Maheswaran, Bhuvaneeshwaran V, Hemanathan M, and Jawahar K. "IoT Based coal mine safety monitoring and controlling." Journal of University of Shanghai for Science and Technology 23, no. 07 (July 24, 2021): 1205–9. http://dx.doi.org/10.51201/jusst/21/07287.
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Many coal miners are concerned about their safety in the workplace. Within subsurface mines, poor ventilation exposes workers to toxic gases, heat, and dust, which can lead to sickness, injury, and death. With the aid of an ARM controller, this work proposes a concept for an Internet of things (IoT), wireless sensor network (WSN) that can track temperature, humidity, and gas in an underground mine. This device uses a low-power, less-cost Arduino UNO, Node MCU, DHT11 sensor, gas sensor, fire sensor to detect fire and send an alarm, and LDR to detect light depending on light levels. Conventional coal mineshaft observing frameworks are regularly wired organization frameworks that assume a significant part in guaranteeing coal mineshaft security. With the ceaseless extension of mining zones and profundity in coal mineshafts, numerous laneways have become visually impaired territories with various secret risks. Furthermore, laying cables, which is costly and time-consuming, is inconvenient. To address the issues, a coal mine safety monitoring system based on a wireless sensor network and the Internet of Things, which can increase the monitoring level is created. Many micro-sensor nodes with small volumes and low costs make up an IoT and wireless sensor network.
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Bajema, Robb A., Travis L. DeVault, Peter E. Scott, and Steven L. Lima. "Reclaimed Coal Mine Grasslands and Their Significance for Henslow's Sparrows in the American Midwest." Auk 118, no. 2 (April 1, 2001): 422–31. http://dx.doi.org/10.1093/auk/118.2.422.
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Abstract Present methods of surface coal-mine reclamation in the Midwest produce large grasslands, some of which exceed 2,000 ha in extent. Total “mine grassland” production in southwestern Indiana alone is well in excess of 70 square miles (180 km2). Our work in 19 reclaimed coal mines in southwestern Indiana indicates that mine grasslands harbor many Henslow's Sparrows (Ammodramus henslowii). We base that conclusion on point-count and line-transect surveys that yielded between 200–300 singing male Henslow's Sparrows during the 1997 and 1998 breeding seasons. Those survey results imply an uncorrected population density of ∼0.10 males per hectare, and a corrected density of ∼0.16 males per hectare (correcting for undetected males). Extrapolating this corrected density to total habitat coverage suggests an overall population of a few thousand Henslow's Sparrows in the mine grasslands of southwestern Indiana. Small-scale vegetational surveys suggest that much of the within-mine variation in Henslow's Sparrow abundance reflects local vegetative structure, with males preferring sites typically associated with that species of bird: tall, dense grass-dominated vegetation with a substantial litter layer. Management for this kind of vegetative structure could greatly increase the number of Henslow's Sparrows inhabiting reclaimed mines. Midwestern mine grasslands could play a significant role in stabilizing the populations of Henslow's Sparrows and other grassland birds.
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BALOVTSEV, Sergey, Olga SKOPINTSEVA, and Konstantin KOLIKOV. "Aerological risk management in preparation mining of coal mines." Sustainable Development of Mountain Territories 14, no. 1 (March 30, 2022): 107–16. http://dx.doi.org/10.21177/1998-4502-2022-14-1-107-116.
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Objective. The purpose of the research is to assess the indicators of aerological risk in the development workings of highly gas-rich coal mines. Introduction. The results of a retrospective analysis are presented, substantiating that the vast majority of explosions of dust-methane-air mixtures occur in development workings, and 63.8% of their gassing with methane to explosive concentrations is associated with ventilation disorders. Methodology. The assessment of aerological risk consists in the calculation of some indicators that reflect the measure of danger, in which an accident may occur, caused by the excess of the values of the mine atmosphere parameters in comparison with the normative ones. Indicators of the main hazards and vulnerability of ventilation schemes and methods make up the general structure of risk in development workings. Results. The methodological bases for assessing and forecasting the aerological risk of accidents in development workings are presented. A formula for calculating the predictive indicator of aerological risk is given. In accordance with the methodology, it is possible to quantify the reduction in the level of aerological risk when managing outgassing with the help of degassing. Discussion. Calculations have shown that the schemes and methods of ventilation of dead-end workings, in which there is a large degree of influence of the activity of mixing gases in the bottomhole zone and a small degree of influence of the exhaust gas zone on ventilation, are the most effective, with a normal level of safety. The values of the predicted upper-air risk indicator reach unity for the schemes and methods of ventilation of dead-end workings with a low degree of gas mixing activity in the bottomhole zone and a high degree of influence of the exhaust gas zone on ventilation, which indicates an extremely high level of explosiveness. Conclusions. Application of the developed methodology allows not only forecasting aerological risks during design, but also justification of aerological safety.
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Zhang, Jing, Qingxia Wang, Wannian Guo, and Longlong Li. "A Support Vector Machine Based Prediction on Sensitivity to Coal Ash Blast for Different Degrees of Deterioration." Journal of Sensors 2022 (August 8, 2022): 1–12. http://dx.doi.org/10.1155/2022/7604338.
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Coal ash blast is a potential hazard that causes serious disasters in coal mines. In explosion control, research work on coal ash sensitivity prediction is of practical importance to improve accuracy, reduce blindness of explosion protection measures, and strengthen targets. The potential and destructive characteristics of coal ash blast vary greatly from coal to coal, especially in coal mines with complex and changing environments, where the characteristics of coal ash blast show great variability under the influence of various factors. In addition, due to the lack of systematic and comprehensive understanding of the occurrence mechanism of coal ash blast, it is necessary to conduct systematic research on the occurrence mechanism of coal ash blast. Current coal ash blast sensitivity summarizes and concludes prediction methods to create reliable predictions for coal ash blast. A new general learning method, support vector machine (SVM), has been developed, which provides a unified framework for solving limited sample training problems and can better solve small sample training problems. With the purpose of determining the coal mine problem and coal ash sensitivity prediction sensitivity indicators and thresholds, the SVM method is used to set the sensitivity function of each prediction indicator, and the sensitivity of each prediction indicator for the proposed study mine is expressed quantitatively. The experimental results show that the prediction accuracy of SVM for positive and negative categories is 15.6% higher than that of BP neural network and 35.1% higher than that of Apriori algorithm. Therefore, the prediction effectiveness of the SVM algorithm is proved. Therefore, it is practical to adopt SVM method for prediction on sensitivity to coal ash blast and apply the latest statistical learning theory SVM to predict the risk of coal ash.
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Qian, Bin, and Hong Ying Zhang. "Safety Analysis and Design of Wireless Monitoring System." Advanced Materials Research 605-607 (December 2012): 844–47. http://dx.doi.org/10.4028/www.scientific.net/amr.605-607.844.
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In recent years, China's coal industry, a gas explosion frequently on people's lives and property caused a great threat, in order to reduce this from happening, our large, medium and small coal mines with high gas or gas outburst after another mine monitoring and control system in the equipment, particularly equipment wireless monitoring system has greatly enhanced the level of mine safety and production safety management efficiency. In this paper, computer technology allows for wireless monitoring system for a more detailed analysis of the description.
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Zhang, Jiuling, Gaoyang Ruan, and Jianguang Chen. "Experimental Study of the Source of CO Anomalies in Mines Based on Microscopic Changes." Fire 5, no. 3 (April 25, 2022): 57. http://dx.doi.org/10.3390/fire5030057.
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The phenomenon of abnormal CO emergence occurred in a working face of Tangshan mine, and the CO source was analyzed from the two perspectives of CO detection method optimization and microstructure changes in the low-temperature environment of the coal body. Then, the critical index system was optimized. The CO identification tube test results and gas chromatograph test results are combined to derive a fitting formula, and the CO identification tube test results are used as the independent variable to obtain the gas chromatograph test results, which can effectively eliminate the error of small CO identification tube test results. The analysis of raw coal and coal samples heated by water bath at 30 °C, 40 °C, and 50 °C was carried out using low temperature liquid nitrogen adsorption and thermogravimetric and infrared spectroscopy experiments. It was found that the pore structure of the coal body developed as the temperature increased; the oxidation reaction occurred in the low-temperature state when heat was absorbed to produce CO. The thermal decomposition of carbonyl group was found to be the main source of CO. Finally, the index of spontaneous combustion of coal is optimized according to the temperature, and the index systems represented by O2/(CO2+CO), CH4 and CO2/CO were determined from 30~80 °C, 90~180 °C and 18~240 °C, respectively.
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Zhang, Jiuling, Gaoyang Ruan, and Jianguang Chen. "Experimental Study of the Source of CO Anomalies in Mines Based on Microscopic Changes." Fire 5, no. 3 (April 25, 2022): 57. http://dx.doi.org/10.3390/fire5030057.
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The phenomenon of abnormal CO emergence occurred in a working face of Tangshan mine, and the CO source was analyzed from the two perspectives of CO detection method optimization and microstructure changes in the low-temperature environment of the coal body. Then, the critical index system was optimized. The CO identification tube test results and gas chromatograph test results are combined to derive a fitting formula, and the CO identification tube test results are used as the independent variable to obtain the gas chromatograph test results, which can effectively eliminate the error of small CO identification tube test results. The analysis of raw coal and coal samples heated by water bath at 30 °C, 40 °C, and 50 °C was carried out using low temperature liquid nitrogen adsorption and thermogravimetric and infrared spectroscopy experiments. It was found that the pore structure of the coal body developed as the temperature increased; the oxidation reaction occurred in the low-temperature state when heat was absorbed to produce CO. The thermal decomposition of carbonyl group was found to be the main source of CO. Finally, the index of spontaneous combustion of coal is optimized according to the temperature, and the index systems represented by O2/(CO2+CO), CH4 and CO2/CO were determined from 30~80 °C, 90~180 °C and 18~240 °C, respectively.
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Zhang, Junwen, and Yulin Li. "The Stability of Gob-Side Entry Retaining in a High-Gas-Risk Mine." Advances in Civil Engineering 2019 (January 13, 2019): 1–12. http://dx.doi.org/10.1155/2019/7540749.
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There are series of problems faced by most of the coal mines in China, ranging from low-coal recovery rate and strained replacement of working faces to gas accumulation in the upper corner of coalfaces. Based on the gob-side entry retaining at the No. 18205 working face in a coal mine in Shanxi Province, theoretical analysis, numerical simulation, and engineering practice were comprehensively used to study the mechanical characteristics of the influence of the width of the filling body beside the roadway and the stability of surrounding rock in a high-gas-risk mine. The rational width of the filling body beside the roadway was determined, and a concrete roadway-side support with a headed reinforcement-integrated strengthening technique was proposed, which have been applied in engineering practice. The stability of the filling body beside the roadway is mainly influenced by the movement of the overlying rock strata, and the stability of the surrounding rock can be improved effectively by rationally determining the width of the filling body beside the roadway. When the width of the roadway-side filling body is 2.5 m, the surrounding rock convergence of the gob-side entry retaining is relatively small at only 5% of the convergence ratio. It has been shown that the figure for roof separation is relatively low, and strata behaviors are relatively alleviated and gas density do not exceed the limit, which are the best results of gob-side entry retaining. The results of this research can provide theoretical guidance for excavation of coal mines with similar geological conditions and have some referential significance to safety and efficient production in coal mines.
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GALIEV, Zhaken Kakitaevich, and Nadezhda Valentinovna GALIEVA. "Coal industry development strategy in domestic and foreign markets." NEWS of the Ural State Mining University, no. 4 (December 20, 2020): 212–17. http://dx.doi.org/10.21440/2307-2091-2020-4-212-217.
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Relevance. In the current context, the cost of coal products is growing. Labor productivity in coal mines and open-pit mines is significantly lower than the corresponding indicator in North America and Australia, a significant proportion of unprofitable enterprises, despite the fact that a third of the world’s coal resources and a fifth of the proven reserves are concentrated in the Russian Federation. In these circumstances, the substantiation of the strategic development of the coal industry on the basis of a SWOT analysis is of great importance. Purpose of the study is to substantiate the strategic vision for the development of the coal industry, priorities for the functioning of coal mining enterprises. Research methods are scientific generalization, method of system analysis and analogies. Results. In the course of the study, the possibilities of functioning of coal mining enterprises, threats to the coal industry, strengths and weaknesses of their activities were identified. The ability to function is determined by the presence of huge coal reserves in Russia, the leadership in its production and export, and a significant share of coking coal grades. The identified threats include: a significant decrease in prices on the world market and coal consumption in the domestic market, an increase in the average transportation distance and the risks of introducing environmental restrictions. The weaknesses in the activities of coal mining enterprises, requiring appropriate measures to be taken to liquidate them, come down to the following: increased operating costs, low labor productivity, a significant number of small mines and open-pit mines that hinder the effective development of the industry as a whole. At the same time, the strategy for further development should focus on the strengths of the coal mining enterprises. These include lower capital investments based on conventional fuel, significantly lower than in the oil and gas industry, therefore, during the period of ensuring sustainable development of the economy as a whole, the development of the coal industry will require lower costs, which creates conditions for the development of other related industries, the possibility of introducing an economic mechanism of inter-fuel competition, as well as the effective functioning of the market structure within the “free” oligopoly. Increasing the competitiveness of coal mining enterprises requires the use of accelerated depreciation methods at export-oriented enterprises, the introduction of problem-solving technology at large coal mining enterprises, the establishment of a rational ratio of the used imported and Russian equipment, and the containment of the growth in the cost of railway transport services. The focus on the implementation of the concept of creating a digital industrial enterprise in the industry plays a special role. A number of measures should be taken to improve financial stability. Conclusions. The identified opportunities and threats, as well as the strengths and weaknesses of the activities of coal mining enterprises, serve as the basis for substantiating the “Strategy for the development of the coal industry”, determine promising directions for the future of coal mining enterprises.
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Cygankiewicz, Janusz. "Determination of Critical Conditions of Spontaneous Combustion of Coal in Longwall Gob Areas / Wyznaczanie Warunków Krytycznych Samozapalania Węgla W Zrobach Ścian." Archives of Mining Sciences 60, no. 3 (September 1, 2015): 761–76. http://dx.doi.org/10.1515/amsc-2015-0050.
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Abstract Decades of experience in the fight against endogenous fire hazard in coal mines indicate a major influence of certain conditions in a given area of the mine on the possibility of fire occurrence, such as: susceptibility of coals to spontaneous combustion, oxygen content in the air incoming to the self-heating coal, conditions of heat exchange between the self-heating coal mass and the environment This paper presents a numerical method for determining the critical conditions of spontaneous combustion of coal in longwall gob areas, i.e. conditions under which spontaneous combustion may occur. It has been assumed that crushed coal in the gob has a shape of a flat layer adjacent from the roof and floor side to the rocks. Our considerations have been limited to coals containing small amount of moisture. A simple model of oxidation kinetics on the coal surface expressed by the Arrhenius equation has been adopted. This model assumes that oxidation rate is independent of the amount of oxygen absorbed by coal. The rate of reaction depends only on temperature, with the parameters of the equation changing after the coal has reached the critical temperature. The article presents also a mathematical model of spontaneous heating of the coal layer in the gob area. It describes the heat balance in the coal as well as the oxygen and heat balance in the flowing gases. The model consists of a system of differential equations which are solved using numerical techniques. The developed computer program enables to perform the relevant calculations. In this paper, on the example of coal from a seam 405, we present the method for determining the following critical parameters of the layer of crushed coal: thickness of the layer, oxygen content in a stream of gases flowing through the layer and thermal conductivity of surrounding rocks.
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Bogusz, Anna, and Mirosława Bukowska. "Specific Energy of Hard Coal Under Load." Studia Geotechnica et Mechanica 37, no. 1 (March 1, 2015): 9–16. http://dx.doi.org/10.1515/sgem-2015-0002.
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Abstract The article presents results of experimental tests of energy parameters of hard coals under loading, collected from research sites located within five main geologic structures of Upper Silesian Coal Basin (GZW) - Main Trough, Main Anticline, Bytom Trough, Rybnik Trough and Chwałowice Trough. Coals from12 mines were analysed, starting with seams of group 200, through groups 400, 500, 600 and, finally, seams of group 700. Coal of each of the groups of seams underwent uniaxial compression stress of the energy parameters, in a servo-controlled testing machine MTS-810NEW, for the full range of strain of the tested coal samples. Based on the tests the dependence of different types of specific energy of longitudinal strain of coals on the value of uniaxial compression strength was determined. The dependence of the value of dissipated energy and kinetic energy of coals on the uniaxial compression strength was described with a linear function, both for coals which due to their age belong to various bed sand for various lithotypes of coal. An increase in the value of dissipated energy and in kinetic energy was observed, which was correlated with an increase in uniaxial compression strength of coal. The share of dissipated energy is dominant in the total energy of strain. Share of recoverable energy in the total energy of strain is small, independent of the compression strength of coals and is at most a few per cent high. In coals of low strength and dominant share of dissipated energy, share of recoverable energy is the biggest among the tested coals. It was shown that following an increase in compression strength the share of recoverable energy decreases, while the share of dissipated energy in the total energy increases. Further studies of specific energy of longitudinal strain of rocks in the full-range strain will be the next step inperfecting methodology of research into natural rock burst susceptibility of Carboniferous rock mass and changes in the susceptibility resulting from mining activity.
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Cheng, Shixing, Zhanguo Ma, Peng Gong, Kelong Li, Ning Li, and Tuo Wang. "Controlling the Deformation of a Small Coal Pillar Retaining Roadway by Non-Penetrating Directional Pre-Splitting Blasting with a Deep Hole: A Case Study in Wangzhuang Coal Mine." Energies 13, no. 12 (June 15, 2020): 3084. http://dx.doi.org/10.3390/en13123084.
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In longwall mining of coal mines, the large deformation of small pillar retaining roadways creates difficulties for the safe and efficient retreating of the mining panel. Based on the engineering background of a small coal pillar retaining roadway in Wangzhuang coal mine, pressure relief technology for non-penetrating directional pre-splitting blasting with a deep hole ahead was proposed. The influence of the non-penetrating fracture length on the pre-splitting effect was studied by numerical simulation. The results showed that the vertical stress in the coal pillar center, the small pillar retaining roadway deformation, and the energy accumulation on the pillar decreased with an increase in the non-penetrating fracture length. The vertical stress at the working face end increased with an increase in the non-penetrating fracture length. The field application and monitoring results indicated that non-penetrating directional pre-splitting blasting could effectively control the deformation of small pillar retaining roadways. The roof-to-floor and rib-to-rib maximum convergences of the 6208 tail entry were reduced by 53.66% and 52.62%, respectively, compared to the results with no blasting. The roadway section met the demands of mining panel high-efficiency retreating, thereby demonstrating the rationality of the technical and numerical simulation results. The research results shed light on the improvement of small coal pillar retaining roadway maintenance theory and technology.
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Wang, Yanxiang, Daolong Yang, Bangsheng Xing, Tingting Zhao, Zhiyi Sun, Qianqian Huang, and Qian Li. "Recent Patents on Thin Coal Seam Mining Equipment." Recent Patents on Mechanical Engineering 13, no. 2 (May 31, 2020): 99–108. http://dx.doi.org/10.2174/2212797613666200221143251.
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Background:: China's thin and extremely thin coal seam resources are widely distributed and rich in reserves. These coal seams account for 20% of the recoverable reserves, with 9.83 billion tons of industrial reserves and 6.15 billion tons of recoverable reserves. Objective: Due to the complex geological conditions of the thin coal seam, the plow mining method cannot be effectively popularized, and the drum mining method is difficult to be popularized and applied in small and medium-sized coal mines, so it is necessary to find other more advantageous alternative mining methods. Methods: The equipment integrates mining operations, conveying operations, and supporting operations, and is suitable for mining short and extremely thin coal seam with a height of 0.35m-0.8m and width of 2m-20m. It has the advantages of the low body of the shearer, no additional support on the working face, and small underground space. The mining efficiency of thin coal seam and very thin coal seam can be improved and the mining cost can be reduced. Results: Thin coal seam shear mining combines mining, conveying, and supporting processes together and has the advantages of a low fuselage, no extra support required for the working face, and feasibility in a small underground space. Conclusion: The summarized mining method can improve the mining efficiency of thin and extremely thin coal seams, reduce mining costs, and incorporate green mining practices, which take both mining economy and safety into account.
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Zeng, Aiping, Lei Yan, Yaping Huang, Enming Ren, Tao Liu, and Hui Zhang. "Intelligent Detection of Small Faults Using a Support Vector Machine." Energies 14, no. 19 (September 30, 2021): 6242. http://dx.doi.org/10.3390/en14196242.
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The small fault with a vertical displacement (or drop) of 2–5 m has now become an important factor affecting the production efficiency and safety of coal mines. When the 3D seismic data contain noise, it is easy to cause large errors in the prediction results of small faults. This paper proposes an intelligent small fault identification method combining variable mode decomposition (VMD) and a support vector machine (SVM). A fault forward model is established to analyze the response characteristics of different seismic attributes under the condition of random noise. The results show that VMD can effectively realize the attenuation of random noise and the seismic attributes extracted on this basis have a good correlation with the small fault. Through the analysis of the SVM algorithm and the fault forward model, it is proved that it is feasible to realize intelligent predictions of small faults by using seismic attributes as the input of a SVM. The fault prediction method using a SVM that is proposed in this paper has higher accuracy than the principal component analysis method, as the prediction results have important guiding significance and reference value for later coal mining. Therefore, the method presented in this paper can be used as a new intelligent method for small fault identification in coal fields.