scholarly journals Assessment of the effective working time on the mining output of the mechanized longwall (coal seam 11) in Ha Lam coal mine

2020 ◽  
Vol 61 (4) ◽  
pp. 95-101
Author(s):  
Hung Phi Nguyen ◽  
Tung Manh Bui ◽  
Dung Tien Thai Vu ◽  
Hanh My Thi Nguyen ◽  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Negative Impact ◽  
Working Time ◽  
Longwall Face ◽  
Mean Flow ◽  
Daily Output ◽  
Geological Conditions ◽  
The Mean ◽  
Production Organization

The mechanizetion of Ha Lam coal seam 11 was designed with mining output of 600.000 tous per year. In fact, due to the negative impact of geological conditions as well as the irrationality of the initial production organization, the mining output of the longwall is not reached according to the designed capacity. The paper proposes a method to determine the effective working time of the actual longwall based on each component stage. For specific conditions at coal seam 11 in Ha Lam coal mine. The mean flow rate of the mining stream is considered as a directional factor of the linear function describing the relation between the daily output and the effective mining in the longwall face. This relation is also considered as motivation in particular for supervisory personnel, as it shows advantages resulting from elongation of this time, as well as it shows possible losses of the daily output in a case when the effective working time is given longwall face was shortened.

scholarly journals Method of the Assessment of the Influence of Longwall Effective Working Time Onto Obtained Mining Output

2016 ◽  
Vol 61 (4) ◽  
pp. 967-977 ◽  
Author(s):  
Ryszard Snopkowski ◽  
Aneta Napieraj ◽  
Marta Sukiennik
Keyword(s):  
Linear Function ◽  
Flow Rate ◽  
Working Time ◽  
Longwall Face ◽  
Mean Flow ◽  
Daily Output

Abstract Method of the influence of assessment of longwall effective working time onto obtained mining output, has been discussed in the present study. Mean flow rate of the winning stream being also considered as directional factor of linear function describing relation between daily output and effective mining in the longwall face, has been determined. Such relation – presented also graphically in form of the diagram – determines significance and influence of the effective working time onto obtained mining output. This relation should be considered as motivation in particular for supervisory personnel, as it shows advantages resulting from elongation of this time, as well as it shows possible loses of the daily output in a case, when the effective working time in given longwall face was shortened.

scholarly journals PATTERNS OF CONVEYOR EXCAVATION DEFORMATION IN MINING AND GEOLOGICAL CONDITIONS OF THE KRASNOLYMANSKA COAL MINE

2020 ◽  
pp. 176-183
Author(s):  
Oleksandr Shashenko ◽  
◽  
Vladyslava Cherednyk ◽  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Field Research ◽  
Coal Mass ◽  
Longwall Face ◽  
Influence Zone ◽  
Geological Conditions ◽  
Mining Coal ◽  
Seam Mining ◽  
Mass Deformation

Purpose. carrying out field researches of the conveyor excavation`s state and establishing geomechanical patterns based on the data, that were obtained in the mining and geological conditions of the Krasnolymanska coal mine. Methodology. Mine field researches of the conveyor excavation deformed state, which is under the influence of the longwall face, and moves in time and space, were carried out. The observation was performed by using a measuring station, which included five measuring points. The results of measurements were generalized and the excavation contour deformation features at various stages of mining coal seam were revealed. Results. Dependencies, that characterize the process of coal mass deformation around the mine at various stages of its exploitation. are obtained. During exploitation processes of the conveyor excavation relative to the longwall face, that gradually pass through four geomechanical situations in mining and geological conditions of the Krasnolymanska coal mine, are established – outside influence zone, in the influence zone, within the longwall face, outside the longwall face. These situations differ in the nature of roof and floor deformation, the vertical convergence of which at each stage changes linearly in time and goes to zero at a distance of 23 meters outside the longwall face. These indicators give reason to consider the roof rocks in the longwall as that sink without breaking the continuity, and also to perform the calibration of geomechanical models based on this. Scientific novelty of the research is new patterns establishment of the coal mass deformation, which contain the conveyor excavation, in the process of the coal seam mining in specific mining and geological conditions. Practical value of the research planned to be carried out on the basis of data obtained after field research is allowed to develop a geomechanical model of active methane accumulation zones searching. The model is applied for further industrial use purposes and to improve the safety of coal mining.

Reasonable Entry Layout of Lower Seam in Multi-Seam Mining Based on Numerical Simulation

2013 ◽  
Vol 295-298 ◽  
pp. 2980-2984
Author(s):  
Xiang Qian Wang ◽  
Da Fa Yin ◽  
Zhao Ning Gao ◽  
Qi Feng Zhao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Coal Seam ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Geological Conditions ◽  
Seam Mining

Based on the geological conditions of 6# coal seam and 8# coal seam in Xieqiao Coal Mine, to determine reasonable entry layout of lower seam in multi-seam mining, alternate internal entry layout, alternate exterior entry layout and overlapping entry layout were put forward and simulated by FLAC3D. Then stress distribution and displacement characteristics of surrounding rock were analyzed in the three ways of entry layout, leading to the conclusion that alternate internal entry layout is a better choice for multi-seam mining, for which makes the entry located in stress reduce zone and reduces the influence of abutment pressure of upper coal seam mining to a certain extent,. And the mining practice of Xieqiao Coal Mine tested the results, which will offer a beneficial reference for entry layout with similar geological conditions in multi-seam mining.

scholarly journals Determination of cyclic filling length in gob-side entry retained with roadside filling and its application

2020 ◽  
Author(s):  
Zizheng Zhang ◽  
Jianbiao Bai ◽  
Xianyang Yu ◽  
Weijian Yu ◽  
Min Deng ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Difference Method ◽  
Suggested Method ◽  
Stress Difference ◽  
Thick Coal Seam ◽  
Mechanics Model ◽  
Working Face ◽  
Geological Conditions ◽  
The Relationship

Abstract Gob-side entry retained with roadside filling (GER-RF) plays a key role in achieving coal mining without pillar and improving the coal resource recovery rate. Since there are few reports on the cyclic filling length of GER-RF, a method based on the stress difference method is proposed to determine the cyclic filling length of GER-RF. Firstly, a stability analysis mechanics model of the immediate roof above roadside filling area in GER was established, then the relationship between the roof stress distribution and the unsupported roof length was obtained by the stress difference method. According to the roof stability above roadside filling area based on the relationship between the roof stress and its tensile strength, the maximum unsupported roof length and rational cyclic filling length of GER-RF. Combined with the geological conditions of the 1103 thin coal seam working face of Heilong Coal Mine and the geological conditions of the 1301 thick coal seam working face of Licun Coal Mine, this suggested method was applied to determine that the rational cyclic filling lengths of GER-RF were 2.4 m and 3.2 m, respectively. Field trial tests show that the suggested method can effectively control the surrounding rock deformation along with rational road-in support and roadside support, and improve the filling and construction speed.

Coal Seam Group Protection Layer Face Causes and Characteristics Analysis of Dynamic Phenomenon

2012 ◽  
Vol 550-553 ◽  
pp. 502-505
Author(s):  
Yong Jiang Zhang ◽  
Xian Zheng Meng ◽  
Zun Yu Xu
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Protective Layer ◽  
Test Area ◽  
Mine Safety ◽  
Dynamic Phenomenon ◽  
Geological Conditions ◽  
Characteristics Analysis ◽  
Safety Production ◽  
Mining Face

In Xinji Coal Mine under complicated geological conditions, regional faults. Experimental zone for near coal seam group mining(6-1,7-1,7-2,8 seam), The objective conditions with protective layer . The minefield of soft broken coal seam, Soft layered coal firmness coefficient f = 0.18. In the test area of 210601,210603 6-1seam protective layer mining face during the period, there were 8 abnormal gas dynamic phenomenon, To the coal mine safety production brought hidden trouble. On the basis of dynamic phenomenon occurring phenomenon, analysis of the dynamic phenomena, combined with the test area actual situation, summed up the6-1coal power causes, for guiding the 6-1safety mining and provide a theoretical basis, has important significance.

scholarly journals Effect of Long Working Hours on Depression and Mental Well-Being among Employees in Shanghai: The Role of Having Leisure Hobbies

2019 ◽  
Vol 16 (24) ◽  
pp. 4980
Author(s):  
Zan Li ◽  
Junming Dai ◽  
Ning Wu ◽  
Yingnan Jia ◽  
Junling Gao ◽  
...  
Keyword(s):  
Psychological Health ◽  
Negative Impact ◽  
Working Hours ◽  
Well Being ◽  
Working Time ◽  
World Health ◽  
Long Working Hours ◽  
The Mean ◽  
The Impact ◽  
Mental Well Being

Our aim is to examine the associations between long working hours and depression and mental well-being among the working population in Shanghai, as well as to identify the impact of having hobbies on these relationships. A cross-sectional study was conducted in Shanghai, with depression assessed by the Patient Health Questionnaire-9 (PHQ-9) scale and mental well-being assessed by the World Health Organization five-item Well-Being Index (WHO-5) scale. The phenomenon of long working hours (69.3%) was quite common among employees in Shanghai, and the rate of working over 60 h was 19.3%. Those who worked over 60 h had the highest prevalence of poorer mental health compared with individuals working ≤40 h per week. After adjustment in the logistic regression model, those who reported weekly working time over 60 h were 1.40 (95%CI: 1.03–1.90) and 1.66 (95%CI: 1.26–2.18) times more likely to have depression and poor mental well-being (PMWB), respectively. Adjusted ORs for having hobbies were 0.78 (95%CI: 0.62–0.97) and 0.62 (95%CI: 0.51–0.75), respectively. Meanwhile, having hobbies could significantly lower the mean score on the PHQ-9 and elevate the mean score on the WHO-5 in each working time group, with no interaction effect. Long working hours could have a significantly negative impact on workers’ psychological health. Importantly, having hobbies in their daily lives might help to mitigate the adverse effects of long working hours on workers’ depression and mental well-being.

scholarly journals Modeling Rock Fracture Propagation and Water Inrush Mechanisms in Underground Coal Mine

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Shichuan Zhang ◽  
Baotang Shen ◽  
Yangyang Li ◽  
Shengfan Zhou
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Rock Fracture ◽  
Water Inrush ◽  
Water Channel ◽  
Karst Collapse ◽  
Mining Equipment ◽  
Geological Conditions ◽  
Fracturing Process ◽  
Collapse Column

Water inrush in underground mines is a major safety threat for mining personnel, and it can also cause major damage to mining equipment and result in severe production losses. Water inrush can be attributed to the coalescence of rock fractures and the formation of water channel in rock mass due to the interaction of fractures, hydraulic flow, and stress field. Hence, predicting the fracturing process is the key for investigating the water inrush mechanisms for safe mining. A new coupling method is designed in FRACOD to investigate the mechanisms of water inrush disaster (known as “Luotuoshan accident”) which occurred in China in 2010 in which 32 people died. In order to investigate the evolution processes and mechanisms of water inrush accident in Luotuoshan coal mine, this study applies the recently developed fracture-hydraulic (F-H) flow coupling function to FRACOD and focuses on the rock fracturing processes in a karst collapse column which is a geologically altered zone linking several rock strata vertically formed by the long-term dissolution of the flowing groundwater. The numerical simulation of water inrush is conducted based on the actual geological conditions of Luotuoshan mining area, and various materials with actual geological characteristics were used to simulate the rocks surrounding the coal seam. The influences of several key factors, such as in situ stresses, fractures on the formation, and development of water inrush channels, are investigated. The results indicate that the water inrush source is the Ordovician limestone aquifer, which is connected by the karst collapse column to No. 16 coal seam; the fracturing zone that led to a water inrush occurs in front of the roadway excavation face where new fractures coalesced with the main fractured zone in the karst collapse column.

scholarly journals The Combustion of Methane from Hard Coal Seams in Gas Engines as a Technology Leading to Reducing Greenhouse Gas Emissions—Electricity Prediction Using ANN

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4429
Author(s):  
Marek Borowski ◽  
Piotr Życzkowski ◽  
Jianwei Cheng ◽  
Rafał Łuczak ◽  
Klaudia Zwolińska
Keyword(s):  
Coal Seam ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Coal Mine ◽  
Electricity Production ◽  
Hard Coal ◽  
Neural Network Models ◽  
Gas Emissions ◽  
Methane Drainage ◽  
Geological Conditions

Greenhouse gases such as carbon dioxide and methane cause global warming and consequently climate change. Great efforts are being made to reduce greenhouse gas emissions with the objective of addressing this problem, hence the popularity of technologies conductive to reducing greenhouse gas emissions. CO2 emissions can be reduced by improving the thermal efficiency of combustion engines, for example, by using cogeneration systems. Coal mine methane (CMM) emerges due to mining activities as methane released from the coal and surrounding rock strata. The amount of methane produced is primarily influenced by the productivity of the coal mine and the gassiness of the coal seam. The gassiness of the formation around the coal seam and geological conditions are also important. Methane can be extracted to the surface using methane drainage installations and along with ventilation air. The large amounts of methane captured by methane drainage installations can be used for energy production. This article presents a quarterly summary of the hourly values of methane capture, its concentration in the methane–air mixture, and electricity production in the cogeneration system for electricity and heat production. On this basis, neural network models have been proposed in order to predict electricity production based on known values of methane capture, its concentration, pressure, and parameters determining the time and day of the week. A prediction model has been established on the basis of a multilayer perceptron network (MLP).

scholarly journals Control of the Internal and External Staggered Distance of Coal Mining Face to the Water-Conducting Fissures in the Overlying Strata of the Near Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhiyuan Jin ◽  
Tao Peng
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Coal Mine ◽  
Calculation Formula ◽  
Coal Seams ◽  
Coal Face ◽  
Geological Conditions ◽  
Mining Face ◽  
Seam Mining ◽  
Water Proof

In Northwest China, rainfall is low, water resources are scarce, and the ecological environment is fragile. For shallow-buried and close-spaced coal seams with a thickness of upper coal bed >60∼70 m, the water-conducting fissures of the overlying rock will not penetrate the water-isolating layer after the upper coal seam is mined; the internal and external gap angles of the water-conducting fissures are not generated from the water-isolating layer. We set out to explore the critical internal and external dislocations for the second significant development of water-conducting fissures in the overlying rock after coal mining under control. A calculation model for the critical internal and external staggered distances of coal mining face in shallow-buried and close-spaced coal seams is established, the calculation formula is given, and the calculation formula for the critical seam mining ratio under the condition of internal staggered mining mode is given. Numerical simulation performed by UDEC methods: taking the overburden strata in the shallow-buried and close-spaced coal seam mining area of Shigetai Coal Mine as a prototype, it was verified that the critical internal and external offsets of the coal mining face in shallow-buried and close-spaced coal seams have a significant effect on the overlying water flow cracks in the mining of the lower coal seam. For the feasibility of developmental control, according to the engineering geological conditions of Shigetai, through the calculation method of external staggered distance, it is concluded that the distance of the open cut of the lower coal face and the upper coal face is only 21∼27 m, which is much smaller than the water barrier. It does not produce the critical distance of the water-conducting cracks. Therefore, in the process of mining the lower coal seam, the water-proof layer will produce water-conducting cracks, lose its water-proof performance, and cause water loss. This is also the cause of the water inrush accident in Shigetai Coal Mine.

Similarity simulation study on displacement and stress changes response to coal mining in Longdong coal mine, China

2020 ◽  
pp. qjegh2020-111
Author(s):  
Kai Huang ◽  
Long Xu ◽  
Fusheng Zha ◽  
Zhitang Lu ◽  
Jiwen Wu ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Water Inrush ◽  
Coal Pillar ◽  
Working Face ◽  
Field Investigations ◽  
Geological Conditions ◽  
Stress Changes ◽  
Continuous Mining ◽  
The Stability

The complicated geological conditions, including the Fault Sun, in East No. 2 mining sub-area of the Longdong coal mine will influence the stability of strata during mining, leading to serious geological hazards. To circumvent this issue, a similarity simulation experiment was designed and performed in this study, in which the failure characteristics and evolution of displacement and stress within the strata were investigated, and the optimum width of a waterproof coal pillar was determined. The results showed that, as the working face progressed, the coal seam roof gradually deformed, from initial caving of the immediate roof to complete movement and curved subsidence of the entire roof. Significant changes in displacement and stress within the coal seam roof were recorded, and these increased during continuous mining activity. Displacement and stress difference on either side of the fault gradually increased and reached remarkable values with increase in mining distance. On the basis of the experiment results, water inrush is believed to be caused by the interaction between mining and the fault, and, as calculated from parameters collected in field investigations, a waterproof coal pillar of 50 m width should be established to prevent Fault Sun activation, thereby reducing the risk of water inrush from neighbouring aquifers.

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