scholarly journals Research on Optimization of a Solid Filling Mining Face Layout Based on a Combined Clamped Beam Model

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhi-Yong Fu ◽  
Xu-Fei Gong ◽  
Peng-Fei Zhang ◽  
Cun-Wen Wang
Keyword(s):  
Coal Mine ◽  
Unit Weight ◽  
Measure Data ◽  
Beam Model ◽  
Maximum Width ◽  
Face Width ◽  
Mining Depth ◽  
Mining Condition ◽  
Mining Face ◽  
Mining Scheme

Optimizing the mining scheme is an essential work for improving recovery efficiency of filling mining. An optimization equation of mining face width under a gangue mining condition is derived firstly. Then, analysis of the optimization equation of the mining face width is carried out based on the measure data of the F5001 mining face in the Tangshan Coal Mine. At last, the reasonable mining face width is determined combined with numerical simulation. Results show that mining face width and roof subsidence increase with the increase of unit weight and mining depth, but decrease with the increase of the elastic modulus of roof. The maximum width of the mining face is 105 m in Tangshan Coal Mine. When the mining width increases from 66 to 105 m, the increasing percentage of roof subsidence is 15–18%. Roof subsidence is controlled less than 30% of the mining height. The variation range of the maximum roof subsidence is small, which means the mining face width can be designed reasonably through the proposed equation.

scholarly journals A Study of Rockburst Hazard Evaluation Method in Coal Mine

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Zhijie Wen ◽  
Xiao Wang ◽  
Yunliang Tan ◽  
Hualei Zhang ◽  
Wanpeng Huang ◽  
...  
Keyword(s):  
Coal Mine ◽  
Evaluation Method ◽  
Hazard Evaluation ◽  
Energy Capacity ◽  
Rockburst Hazard ◽  
Damage Level ◽  
Mining Depth ◽  
Metal Mine ◽  
Mining Face ◽  
Loading Type

With the increasing of coal mining depth, the mining conditions are deteriorating, and dynamic hazard is becoming more likely to happen. This paper analyzes the relations and differences between rockburst in the coal mine and rockburst in the metal mine. It divides coal mine rockburst into two types including static loading type during roadway excavation process and dynamic loading type during mining face advancing. It proposes the correlation between the formation process of rockburst and the evolution of overlying strata spatial structure of the stope, criterion of rockburst occurrence, new classification, and predictive evaluation method for rockburst hazard that rockburst damage evaluation (RDE) = released energy capacity (REC)/absorbed energy capacity (AEC). Based on the relationship between RDE value and its corresponding level of rockburst hazard, the rockburst hazard can be divided into five types and evaluation index of each type can be achieved. Then the ongoing rockburst damage level can be classified in one of the five types, and the relative parameters, such as hazard extent, controlling measures also can be achieved. This new quantitative method could not only assess the impacting direction of rockburst occurrence, but also verify the effect of preventive measures for rockburst.

The Characteristics of Collapse Columns in Duanwang Minefield and their Influences on Gas Emission Quantities of Coal Faces

2013 ◽  
Vol 634-638 ◽  
pp. 3537-3540
Author(s):  
Xin Xian Zhai ◽  
Xiao Ju Li ◽  
Yan Wei Zhai
Keyword(s):  
Coal Mine ◽  
Production Capacity ◽  
Mining Area ◽  
Mine Safety ◽  
Shanxi Province ◽  
Free Form ◽  
Karst Collapse ◽  
Coal Face ◽  
Gas Emission ◽  
Mining Depth

Duanwang Coal Mine is located at north of Qinshui coalfield in Shanxi province, China, which gently inclined and thick seams have been mined. Authorized production capacity of the coal mine is 1.8Mt/a. With the increase of mining depth, the mine gas emission quantity increased. Karst collapse columns are very developed in the minefield, and the phenomenon of abnormal gas emission always occurred at the coal face and driving gateway around the collapse columns, then the mine became high gassy one from low gassy mine. Using field measurement and theoretical analysis methods, the following conclusion can be drawn. Karst collapse columns have significant influences on gas emission of the coal face and driving gateway. Here are large amount of free form gas into and around the collapse columns, the collapse columns were disclosure while driving gateway, a large amount of the free gas into collapse column would be instantly released, which caused abnormal gas emission at driving gateway, even leading to gas density exceeding limitation by Coal Mine Safety Regulation of China. However, during mining area of the collapse columns, gas emission quantity at coal face was relatively smaller.

Influences of Mining Depths of Coal Faces in Duanwang Coal Mine on the Gas Emission Law

2013 ◽  
Vol 295-298 ◽  
pp. 2874-2878
Author(s):  
Xin Xian Zhai ◽  
Yan Wei Zhai ◽  
Shi Wei Zhang
Keyword(s):  
Theoretical Analysis ◽  
Coal Mine ◽  
Production Capacity ◽  
Control Measures ◽  
Shanxi Province ◽  
Coal Face ◽  
Gas Emission ◽  
Average Value ◽  
Mining Depth ◽  
Selection Of

Duanwang Coal Mine in Shanxi province, China, is located at north of Qinshui coalfield which gently inclined and thick seams have been mined. Authorized production capacity of the coal mine is 1.8Mt/a. With the increase of mining depth, the mine gas emission quantity increased. The mine became high gassy one from low gassy mine. Using field measurement and theoretical analysis methods, the following conclusion can be drawn. Gas emission quantity of coal face is directly correlated with mining depth. With the increase of mining depth, both absolute and relative gas emission quantities at coal face increased. The gradient of gas emission quantity was 0.0438-0.1338m3/t/m, the average value was 0.1062m3/t/m. These results would provide a foundation for prediction of the gas emission quantity and selection of gas control measures.

scholarly journals Study on Fracture and Stress Evolution Characteristics of Ultra-Thick Hard Sandstone Roof in the Fully Mechanized Mining Face with Large Mining Height: A Case Study of Xiaojihan Coal Mine in Western China

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Feng Ju ◽  
Meng Xiao ◽  
Zequan He ◽  
Pai Ning ◽  
Peng Huang
Keyword(s):  
High Strength ◽  
Western China ◽  
Stress Evolution ◽  
Working Face ◽  
Mining Condition ◽  
Evolution Characteristics ◽  
Large Mining Height ◽  
Evolution Laws ◽  
Mining Face ◽  
Mining Height

Ultra-thick hard sandstone roofs present high thickness, poor delamination, and wide caving range. The strata pressure of the working face during actual mining increases, having a significant influence on the safe mining of the working face. Especially, in the mining areas of western China, the fully mechanized mining faces with high mining height and high-strength mining are more prominent. Understanding the fractures and stress evolution characteristics of the ultra-thick hard sandstone roof during actual mining is of high significance to control the dynamic pressure on the working face. In this paper, the typical ultra-thick hard sandstone roof of the Xiaojihan coal mine was taken as an example. The structural and chemical composition characteristics were analyzed. Besides, the fracture characteristics of ultra-thick hard roof during the working face mining were analyzed. Moreover, the fracture structure consistency was verified through physical simulation and a field measurement method. Finally, the stress evolution laws in the ultra-thick hard sandstone roof fracture were studied through numerical simulation. The findings demonstrated that (1) the ultra-thick hard sandstone roof was composed of inlaid coarse minerals, which had compact structure, while the Protodyakonov hardness reached up to 3.07; (2) under the high-strength mining condition of fully mechanized mining face with large mining height, the ultra-thick hard sandstone roof had the characteristics of brittle fracture, with a caving span of 12 m; (3) under the high-strength mining condition of fully mechanized mining face with large mining height, the ultra-thick hard sandstone roof followed the stress evolution laws that were more sensitive to the neighboring goaf. Therefore, it was necessary to reduce the fracture span or layering of ultra-thick hard sandstone roof through the manual intervention method adoption or increase either the strength of coal pillar or supporting body, to resist the impact generated during ultra-thick hard sandstone roof fracture.

scholarly journals Characteristics of New Permanent Magnetic Eddy Current Drive System of the Scraper Conveyor

2021 ◽  
Author(s):  
shuang wang ◽  
Yongcun GUO ◽  
Deyong LI
Keyword(s):  
Eddy Current ◽  
Coal Mine ◽  
Mining Area ◽  
Current Drive ◽  
Drive System ◽  
Model Accuracy ◽  
Working Face ◽  
Scraper Conveyor ◽  
Mining Face ◽  
Motion Characteristics

Abstract This study provides a new permanent magnetic eddy current drive system to solve the ener-gy-saving drive problem of the scraper conveyor working under bad conditions, including overload startup, severe abrasion and pollution. Considering the practical conveying conditions of the scraper chain on a fully mechanised coal mining face, this study creates a mathematical model for the new permanent magnetic eddy current drive system of the scraper conveyor based on its characteristics and indicates the motion characteristics of the scraper chain driven by two wheels. This study verifies the model accuracy with a pre-startup technology depending on the scraper conveyor on the No. 12318 working face of the 8th coal mine in the West No. 1 mining area of the Pansan Coal Mine of the Huainan Mining Group. According to the results, the motion acceleration of the scraper chain based on the new permanent magnetic eddy current drive is lower than that of the scraper chain with a hydraulic coupler under the same running condition and load during startup and acceleration and declines by approximately 14.7%. Consequently, this can decline the startup impact due to the serious abrasion and frequent overload of the scraper chain working under bad conditions.

Applications of Carbon Dioxide Cannon Blasting on the Problem of Triangular Flap Top in Coal Mine Handling Mechanized Mining Face

2012 ◽  
Vol 256-259 ◽  
pp. 71-74
Author(s):  
Yan Bo Zhang ◽  
Er Qiang Li ◽  
Jia Wei Liu ◽  
Xin Jia Leng ◽  
Wen Guo Li
Keyword(s):  
Carbon Dioxide ◽  
Coal Mine ◽  
Effective Solution ◽  
Large Area ◽  
Triangular Flap ◽  
Production Safety ◽  
Mining Face

As mining process in the Mechanized mining face, making it easy come with flap top[1] along the the upward and downward entries. In this paper, through the use of carbon dioxide cannon, we do pre-split blasting experiment on triangular flap top in mechanized mining face, exploring an effective solution to a large area of goaf flap top suddenly breaking down, with the hurricane caused damage and fan-out of toxic and harmful gases, to achieve the purpose of production safety.

scholarly journals Surface Subsidence Prediction Method for Coal Mines with Ultrathick and Hard Stratum

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Hongkai Han ◽  
Jialin Xu ◽  
Xiaozhen Wang ◽  
Jianlin Xie ◽  
Yantuan Xing
Keyword(s):  
Coal Mining ◽  
Coal Mine ◽  
Prediction Method ◽  
Prediction Equation ◽  
Arbitrary Cross Section ◽  
Surface Subsidence ◽  
Strong Impact ◽  
Subsidence Prediction ◽  
Movement Characteristics ◽  
Mining Condition

Overburden conditions consisting of ultrathick and hard stratum (UTHS) are widespread in China and other countries, but existing surface subsidence prediction methods ignore the strong impact of UTHS on surface subsidence. They are thus not applicable for surface subsidence prediction for coal mining with the presence of UTHS. We conducted actual measurements of surface and UTHS subsidence in the Tingnan Coal Mine. The results showed that under the UTHS mining condition, the required gob dimension is much larger than the empirical value when the surface reaches sufficient mining and that the actual measured maximum value of surface subsidence is much smaller than the empirical value. The UTHS subsidence is approximately equal to the surface subsidence. The movement of UTHS has a strong impact on surface subsidence and has a controlling function for it. It was proposed that surface subsidence could be approximately predicted by calculating the UTHS subsidence. The UTHS movement characteristics were studied using Winkler’s theory of beams on an elastic foundation, the subsidence prediction equation of the main sections in the strike and dip directions was obtained under different mining dimensions, and the subsidence prediction equation of any arbitrary cross section parallel to the two main sections was established. Then, the surface subsidence prediction method for coal mining with the presence of UTHS was developed, and the influences of UTHS thickness, strength, and layer position on the surface subsidence were discussed. The Tingnan Coal Mine was taken as an example, and the subsidence curves of the strike and dip main sections were calculated using different mining dimensions. Subsequently, the surface subsidence after the mining of working faces 204, 205, 206, and 207, respectively, was predicted, and the prediction method was verified by comparing the results with the measured surface subsidence results of working faces 204, 205, and 206.

scholarly journals Study on Roof-Coal Caving Characteristics with Complicated Structure by Fully Mechanized Caving Mining

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Yunpei Liang ◽  
Lei Li ◽  
Xuelong Li ◽  
Kequan Wang ◽  
Jinhua Chen ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Research Work ◽  
Maximum Principal Stress ◽  
Complicated Structure ◽  
Mining Technology ◽  
Thick Coal Seam ◽  
Soft Coal ◽  
Mining Depth ◽  
Arch Forms

With mining technology and mechanization degree being improving, fully mechanized caving mining technology (FCM) has become a main method for thick coal seam extraction in China. However, roof-coal caving characteristics in turn restrict its recovery efficiency, especially for the coal seam with complicated structure (CCS), that is, the coal seam comprises hard or soft coal and gangue. In order to explore the key factors influencing the roof-coal caving and recovery characteristics, related research work has been conducted as follows: firstly, a mechanical model of CCS has been established, which indicates the strength of the coal and gangue will directly affect the roof-coal recovery. Meanwhile, based on the geological settings of Qinyuan coal mine, numerical simulation on roof-coal caving law under different thicknesses of hard or soft coal and gangue has been performed using UDEC software. The results show that the maximum principal stress will increase with the increase of mining depth, making the roof-coal to break easily. Furthermore, the range of the plastic zone of the top coal and the damage degree of the top coal increase with the increase of mining depth. Physical modeling results show that when an extraction-caving ratio is 1, the number of times the coal arch forms is 0.43 at every caving, up to a maximum of 3; the number of times coal arch forms with an extraction-caving ratio of 2 is 4.65 times larger than that with an extraction-caving ratio of 1. The probability of coal arch formation with an extraction-caving ratio of 3 is minimal, about 0.4, which is due to that the arch span is large and the curvature is small, so it is difficult to form a stable arch structure. According to the mechanical characteristics of roof-coal in Qinyuan coal mine, deep-hole blasting technique has been used to reduce the fragments of roof-coal crushed. The results show that this technique can effectively improve the recovery of roof-coal.

The Research on Geological Characteristics of the Dafosi Coal Mine Company 40110 Working Face

2012 ◽  
Vol 170-173 ◽  
pp. 1273-1276
Author(s):  
Jia Ming Han
Keyword(s):  
Coal Mine ◽  
Relative Movement ◽  
Practical Application ◽  
Wing Area ◽  
Daily Production ◽  
The Third ◽  
Geological Characteristics ◽  
Working Face ◽  
Sublevel Caving ◽  
Mining Face

40110 working face is arranged as the third Mechanized sublevel caving mining face in the 401 east-wing area along the coal seam by Dafosi company of the Binchang Mining Group Corporation. According to the conclusion based on the research about Binchang area coal geology not only shows the roof and floor lithology, structure, hydrology, the gas, dust features and so on but also proposes mining roadway supporting schemes and putting them into practice. Practical application shows that roadway supporting schemes effectively control the two-sided displacement and relative movement of the roof and floor to ensure the daily production of coal mine.

scholarly journals Size effect of Water-flowing fracture Zone height based on FLAC3D

2020 ◽  
Vol 194 ◽  
pp. 01011
Author(s):  
Chao Zheng ◽  
Lan Yu ◽  
Ning Sun ◽  
Hualong Zhou ◽  
Jiangyi He
Keyword(s):  
Size Effect ◽  
Coal Mine ◽  
Fracture Zone ◽  
Average Distance ◽  
Water Inrush ◽  
Water Diversion ◽  
Effect Of Water ◽  
Face Width ◽  
Working Face ◽  
Simulation Results

The loss of water resources caused by mining fissures is a key factor restricting the green development of coal resources in western mining areas. in order to analyze the influence of mining thickness and face width on the development height of water diversion fracture zone, based on the characteristics of overburden in Xinzhuang Coal Mine, the finite difference software FLAC3D is used to simulate and analyze the size effect of water diversion fracture zone height. The simulation results show that the height of the water diversion fracture zone is positively correlated with the increase of mining thickness and working face width. When the mining thickness is 9m and the width of the working face is 240m, the height of the water diversion fracture zone is 115m, and the average distance between the coal layer 8 of Xinzhuang Coal Mine and the bottom of the Cretaceous aquifer is 106.9m, which may cause water inrush in the mine. Therefore, according to the simulation results and referring to the mining size of part of the mine face in the attached Binchang mining area, it is suggested that the mining thickness of Xinzhuang Coal Mine is about 10m and the width of the working face is not more than 200m.

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