mining system
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2022 ◽  
Author(s):  
Zhe Bing ◽  
Xing Wang ◽  
Zhenliang Dong ◽  
Luobing Dong ◽  
Tao He

Author(s):  
Victor L. Martyanov ◽  
Sergey O. Markov ◽  
Valery F. Kolesnikov ◽  
Ekaterina A. Tyuleneva ◽  
Michal Cehlár ◽  
...  
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2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Cao Khai NGUYEN ◽  
Van Thinh NGUYEN ◽  
Phi Hung NGUYEN ◽  
Van Quang NGUYEN

In the process of underground mining, the mining system changes for various reasons. One ofthe main reasons is changes in the mining production plans, especially the scales and outputs. Nowadays,coal mines in Vietnam have been expanding in width and depth, and so have the mines’ ventilationsystems. Consequently, there will be changes in the alteration of the structure of the design ventilationsystem, which reduces the effectiveness of the ventilation and does not meet the main objective of mineventilation, directly affect the safety of the working environment in the mine. Therefore, it is necessary toresearch the improvement of the ventilation system with the development and specific conditions ofunderground coal mines in Vietnam, improving the efficiency of the ventilation work and assuring thesafety of the mine environment. Cam Thanh coal mine, Ha Long coal company, Vietnam, is the case studyfor this research. The article considers the plan of increases the mining output by more than 1.5 times,propose solutions to improve the ventilation system accordingly, helping the company proactivelyimplement the production plan, ensure the working environment's safety, and reduce the costs of mineventilation.


2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Quang Phuc LE

The deformation and support method of roadways have always been important issues in safemining and production. Vinacomin's statistics show that, by 2021, there will be 64.19 km of roadwaysthat need to be repaired (accounting for 25% of the total new roadways). Thus, the problem of maintainingroadway stability is facing difficulties in underground coal mines in Vietnam. To find out the causes ofroadway failures, a case study at roadways of the Khe Cham I and Khe Cham III coal mines, Vietnam, ispresented in this paper. Based on the results of a detailed field survey, the deformation characteristics ofroadways and the failure mode of support structures were investigated. The results show that the roadwaydeformation is severe and the main support cannot control surrounding rock mass. Also, the destructionof support structure is frequent on reused roadways, affecting production efficiency and work safety.Therefore, to reduce deformation and increase roadway stability, a new support method called “multistageanchor of rock bolt + cable bolt” has been developed and a new longwall mining system with criticalcoal pillar width has been proposed. The new findings of the research can provide references for scientificstudies, and apply them in Vietnam's underground coal mine practices.


2021 ◽  
Vol 937 (4) ◽  
pp. 042088
Author(s):  
G Bulatov ◽  
T Annakulov

Abstract This article presents the results of studies to establish the optimal entry width for an excavator working in conjunction with mobile crushing plants in the development of overburden of the Angren open pit. According to the results of the research, an analytical relationship was established to determine the maximum productivity of the mining system “excavator-mobile crushing-reloading-conveyor complex” with cyclical-flow technology. A structural diagram has been developed that allows you to select the type and determine the main technological parameters of the equipment with the selected criteria for evaluating the effectiveness of the complexes. It has been established that the choice of equipment for conveyor lines should be carried out taking into account the mutual influence of adjacent technological links of the central heating systems, including the influence of the excavator-crushing and crushing-conveyor complexes on the efficiency of their mutual functioning within the framework of the adopted system as a whole. A functional graphical dependence of the excavator performance on the face width was obtained, taking into account the relationship of all technological parameters of the face. It has been established that the maximum excavator productivity of 1478.1 m3/hr is achieved with an excavator entry width of 17.4 m for the conditions of the Angren open pit. The resulting schedule makes it possible to assess the possibility of increasing the operational performance of single-bucket shovel excavators under various conditions of work, as well as to continue the optimization of excavation.


2021 ◽  
Author(s):  
Haoshuai Wu ◽  
Yanlong Chen ◽  
Haoyan Lv ◽  
Qihang Xie ◽  
Yuanguang Chen ◽  
...  

Abstract The highwall miner can be used to mine the retained coal in the end slope of an open-pit mine. However, the instability mechanism of the reserved rib pillar under dynamic and static loads is not clear, which restricts the safe and efficient application of the highwall mining system. In this study, the load-bearing model of the rib pillar in highwall mining was established, the cusp catastrophe theory and the safety coefficient of the rib pillar were considered, and the criterion equations of the rib pillar stability were proposed. Based on the limit equilibrium theory, the limit stress of the rib pillar was analyzed, and the calculation equations of plastic zone width of the rib pillar in highwall mining were obtained. Based on the Winkler foundation beam theory, the elastic foundation beam model composed of the rib pillar and roof under the highwall mining was established, and the calculation equations for the compression of the rib pillar under dynamic and static loads were developed. The results show that with the increase of the rib pillar width, the total compression of the rib pillar under dynamic and static loads approximately decreases in an inverse function, and the compression of the rib pillar caused by static loads of the overlying strata and trucks has a decisive role. Numerical simulation and theoretical calculation were performed in this study. In the Numerical simulation, the coal seam with a buried depth of 122 m and a thickness of 3 m was mined by the highwall miner. According to the established rib pillar instability model of the highwall mining system, it is found that when the mining tunnel width is 3 m, the reasonable width of the rib pillar is at least 1.3 m, and the safety factor of the rib pillar is 1.3. The numerical simulation results are in good agreement with the results of theoretical calculation, which verifies the feasibility of the theoretical analysis of the rib pillar stability. The research results can provide an important reference for the stability analysis of rib pillars under highwall mining.


2021 ◽  
pp. 146144482110588
Author(s):  
Peng Zheng ◽  
Paul C Adams ◽  
Jiejie Wang

Better understanding of social media uses in crisis situations can help improve disaster management by policy-makers, organizations, businesses, and members of the public. It can also build theoretical understanding of how social life and citizenship incorporate social media usage. This study tracks the evolution of public sentiment in Wuhan, China, during the first 12 weeks after the identification of COVID-19 on the Chinese microblogging platform Sina Weibo. Data consist of 133,079 original Sina Weibo posts dealing with the novel coronavirus. The relative prevalence of eight different emotion groups is traced longitudinally using the ROST Content Mining System and the Emotion Vocabulary of Dalian University of Technology. The study finds a progression from confusion/fear, to disappointment/frustration, to depression/anxiety, then finally to happiness/gratitude. It argues that this progression indexes the changing affective energies of digital medical citizenship, which in turn indicates the context for intervention in future crises.


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