scholarly journals A New Gob-Side Entry Layout Method for Two-Entry Longwall Systems

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2084 ◽  
Author(s):  
Rui Wu ◽  
Qingyuan He ◽  
Joung Oh ◽  
Zecheng Li ◽  
Chengguo Zhang
Keyword(s):  
Recovery Rate ◽  
Mining Industry ◽  
Economic Benefits ◽  
Chinese Government ◽  
Hard Roof ◽  
Mine Sites ◽  
Gob Area ◽  
Longwall Mine ◽  
Longwall Top Coal Caving ◽  
Cutting Height

The gob-side entry layout is popular at two-entry longwall mine sites in China for the benefit of improving the coal recovery rate. Currently, two methods have been widely used to develop gob-side entries, including gob-side entry retaining and gob-side entry driving. Gob-side entry retaining maximizes the recovery rate by pillarless mining but increases the difficulty in gob-side entry support. Also, this method has limited applications in hard roof conditions. The gob-side entry driving mine site uses the rib pillar to separate the gob entry and the gob area of the previous panel, which leads to additional coal losses. The waste is more intolerable in large-cutting-height panels and longwall top coal caving panels as the Chinese government limits the minimum recovery rate of longwall panels using these mining methods. In this paper, a new gob-side entry layout method, termed gob-side pre-backfill driving, is established to overcome the shortcomings of the existing methods. The new method eliminates rib pillar losses and enhances gob-side entry stability. The feasibility of gob-side pre-backfill driving is studied by numerical modelling and a field trial at Changcun Mine in China. The results indicate that gob-side pre-backfill driving is an alternative for gob-side entry development. This method is practical and also has the potential to bring significant economic benefits to the mining industry.

scholarly journals Study on Controlling Parameters and Technological Optimization of Strip Longwall Top Coal Caving in Thick Coal Seams

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Bui MANH TUNG ◽  
Le TIEN DUNG ◽  
Liu CHANG YOU ◽  
Pham VAN CHUNG
Keyword(s):  
Recovery Rate ◽  
Technological Parameters ◽  
Coal Seams ◽  
Efficient Operation ◽  
Coal Recovery ◽  
Mining Conditions ◽  
Face Length ◽  
Longwall Top Coal Caving ◽  
Cutting Height ◽  
Selection Of

Based on the geological and mining conditions of face 3107 at Liang Baoshi coal mine, China, the numerical programs FLAC3D 2.10 and PFC2D 2.10 were used to analyze the parameters controlling the failure, caving and the coal recovery rate in Strip Longwall Top Coal Caving (SLTCC). The analyzed parameters are face length in dip direction, mining height, the span of coal caving, and sequence of coal drawing. The results show that the application of SLTCC for a limited face length is not favourable to coal failure, and it increases top coal loss. A sound engineering selection of technological parameters is therefore important to efficient mining in thick coal seams. The numerical results show that a face design of 3 m of cutting height, 0.8 m of caving span, and alternate drawing sequence results in high coal recovery rate, simple mining tasks, and efficient operation of face equipment.

scholarly journals Front Stress Distribution Under the Impact of Cutting Height to Caving Height Ratio in Extra-thick Longwall Top Coal Caving Technology

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Bui MANH TUNG ◽  
Nguyen VAN QUANG ◽  
Nguyen PHI HUNG ◽  
Vo NGOC DUNG ◽  
Do HOANG HIEP
Keyword(s):  
Stress Distribution ◽  
Peak Stress ◽  
Height Ratio ◽  
Research Orientation ◽  
Geological Conditions ◽  
The Face ◽  
New Research ◽  
Longwall Top Coal Caving ◽  
Cutting Height ◽  
The Impact

The extraction with higher cutting height for extra-thick seam is the new research orientation in longwall caving technology. Due to the increase of top coal thickness and of cutting height which leads to the change of cutting/caving height ratio, the rule of roof failure (including top coal caving) and the distribution of stress around the face alter correspondingly. This paper is based on the geological conditions of face 8102 of Tashan-DaTong mine, employing the numerical model by UDEC2D code, analysing the effect of cutting/caving height ratio on the law of stress distribution ahead of the face. When the ratio of cutting/caving height decreases and the cutting height increases, the results of the research have shown that: (i)- peak stress redistributes further ahead of the face and its value manifestly drops; (ii)- the plastic deformation ahead of face significant increases and the zone of plastic strain also expands. It is therefore concluded that the variation of cutting/caving height ratio results in the redistribution of roof pressure, which contributes to the control of roof failure and face stability.

scholarly journals Key Parameters of Roof Cutting of Gob-Side Entry Retaining in a Deep Inclined Thick Coal Seam with Hard Roof

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 934 ◽  
Author(s):  
Jinzhu Hu ◽  
Manchao He ◽  
Jiong Wang ◽  
Zimin Ma ◽  
Yajun Wang ◽  
...  
Keyword(s):  
Numerical Model ◽  
Coal Seam ◽  
Economic Benefits ◽  
Surrounding Rock ◽  
Thick Coal Seam ◽  
Hard Roof ◽  
Coal Recovery ◽  
Rock Structure ◽  
Different Depths ◽  
Dip Angle

Gob-side entry retaining by roof cutting (GERRC) employed in a deep inclined thick coal seam (DITCS) can not only increase economic benefits and coal recovery, but also optimize surrounding rock structure. In accordance with the principles of GERRC, the technology of GERRC in DITCS is introduced and a roof-cutting mechanical model of GERRC is proposed to determine the key parameters of the depth and angle of RC. The results show that the greater the RC angle, the easier the caving of the goaf roof, but the length of cantilever beam increases. The depth of RC should account for the dip angle of the coal seam when the angle is above 20°. Increasing the coal seam dip angle could reduce the volume of rock falling of the goaf roof, but increase the filling height of the upper gangue to slide down. According to numerical model analysis of the stress and displacement of surrounding rock at different depths and angles of RC, when the depth of RC increased from 9 m to 13 m, the distance between the stress concentration zone and the coal side is increased. When the angle of RC increased from 0° to 20°, the value of roof separation is decreased. GERRC was applied in a DITCS with 11 m depth and 20° RC angle, and the field-measured data verified the conclusions of the numerical model.

Study on Technology of Fully-Mechanized Sub-Level Caving Mining Technology in the Datong Permo Carboniferous Coal Seam

2012 ◽  
Vol 616-618 ◽  
pp. 565-568
Author(s):  
Bin Yu ◽  
Jun Zhao ◽  
Hong Chun Xia
Keyword(s):  
Coal Seam ◽  
Mining Area ◽  
Hard Coal ◽  
Control Technology ◽  
Mining Technology ◽  
Hard Roof ◽  
Sublevel Caving ◽  
Seam Mining ◽  
Longwall Top Coal Caving ◽  
And Control

This thesis briefly introduced roof control technology in fully-mechanized sublevel caving mining with hard roof and hard coal seam, Mining technology , gas prevention and comprehensive prevention and control technology in spontaneous combustion of coal, which in longwall top-coal caving face with hydraulic support in thickness seam in the Datong permo carboniferous coal seam . New development directions of fully-mechanized sublevel caving mining technology in the Datong mining area in the next few years.

scholarly journals Health and wellness in the Australian coal mining industry: A cross sectional analysis of baseline findings from the RESHAPE workplace wellness program

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252802
Author(s):  
Aaron Bezzina ◽  
Emma K. Austin ◽  
Trent Watson ◽  
Lee Ashton ◽  
Carole L. James
Keyword(s):  
Coal Mining ◽  
Mining Industry ◽  
Overweight And Obesity ◽  
Workplace Wellness ◽  
Wellness Program ◽  
Shift Workers ◽  
Coal Mining Industry ◽  
Diet And Exercise ◽  
Workplace Factors ◽  
Mine Sites

Overweight and obesity has reach pandemic levels, with two-thirds (67%) of adult Australians classified as overweight or obese. As two of the most significant behavioral risk factors for obesity are modifiable (diet and exercise), there exists an opportunity for treatment through workplace health promotion initiatives. As one of Australia’s largest industries with its own unique workplace factors, the mining industry has previously reported higher than population levels of overweight and obesity. This represented an opportune setting to test the RESHAPE workplace wellness program. RESHAPE is an eight-step framework (based on the WHO ‘Health Workplace Framework and Model’) which aims to provide a sustained approach to wellness in the workplace. This paper presents baseline findings from a pilot study that aimed to implement RESHAPE at three mine sites in NSW, Australia, and investigates the issue of overweight and obesity in the coal mining industry. Across three mine sites, 949 coal miners were examined cross-sectionally on a range of workplace, wellness, health, diet, and exercise factors using a paper-based survey. This was a predominantly male sample (90.4%) with the majority (59.2%) of participants aged 25–44 years. Self-reported height and weight measures indicated that less than 20 percent (18.9%) of participants were in a healthy BMI range, while there were effectively equal numbers of overweight (40.9%) and obese (39.1%) participants. Only 3.5% of participants met the daily recommendation for vegetables (5 serves) and shift-workers had greater association with elevated BMI compared to non-shift workers (B = 1.21, 95% CI: 0.23, 2.20, p = 0.016). Poor nutrition is likely to be a key component in elevated levels of overweight and obesity within this industry, with workplace factors compounding challenges workers face in implementing health behavior change. Future studies would benefit from assessing diet and physical activity knowledge in relation to recommendations and serving sizes.

scholarly journals Environmental Management and Monitoring of Mining Operation in Lao PDR

2014 ◽  
pp. 47-53
Author(s):  
Phengkhamla Phonvisai ◽  
Jiragorn Gajaseni
Keyword(s):  
Environmental Management ◽  
Economic Development ◽  
Lao Pdr ◽  
Mining Industry ◽  
Economic Benefits ◽  
Rapid Expansion ◽  
Developed Country ◽  
Eradication Strategy ◽  
Mining Projects ◽  
The Government

Overall, mining projects make a significant contribution to gross of domestic product (GDP) in Lao People’s Democratic Republic (Lao PDR). Benefits include increased export revenues, provision of royalty and tax income to the government, technology transfer, worker training and the creation of a skilled workforce. This can also lead to improved social, physical, legal and financial infrastructure due to development around the mining areas such as roads, electricity and water distribution. Managed properly, economic benefits from mining projects can benefit future generations,even after operations have ceased. For Lao PDR, rapid expansion of the mining sector is seen as vital to economic development. In the National Socio-Economic Development Plan, mining was prioritized as a key sector to help Lao PDR achieve its goal to graduate from its status as least developed country by 2020. Government revenues from mining projects are a major contributor to the country’s National Growth and Poverty Eradication Strategy. Environmental management and monitoring of the operations of mining projects are essential in order to identify and mitigate potential negative environmental impacts. Such impacts may be minimized through the use of mining industry best practice as well as compliance with Government of Laos (GoL) and international environmental standards and regulations. The environmental management and monitoring process first identifies and quantifies potential impacts of a mine’s operation on land, water, atmospheric and biological resources, as well as on human settlements. Secondly,measures are proposed to avoid or mitigate identified adverse impacts, including a specific requirement for a mine closure and rehabilitation plan.

Numerical Simulation Study on Setting Stopping Line of Working Face in Shuguang Mine

2014 ◽  
Vol 580-583 ◽  
pp. 2554-2557
Author(s):  
Hua Jun Xue ◽  
Jun Chen ◽  
Bo Liu ◽  
Jie Kong ◽  
Zhi Jun Hao
Keyword(s):  
Numerical Simulation ◽  
Recovery Rate ◽  
Coal Pillar ◽  
Economic Benefits ◽  
Surrounding Rock ◽  
Long Term Stability ◽  
Rock Stability ◽  
Working Face ◽  
Stopping Line

The surrounding rock deformation of pedestrian roadway was serious under the influence of the working face. And it has affected the safety and normal use of roadway. To ensure the long-term stability of the pedestrian roadway surrounding rock and increase the coal recovery rate of working face, the paper studied the position of stopping line of 1203 working face by numerical simulation. The results show that setting 115m wide of security coal pillar between 1203 working face and pedestrian roadway that the area of stress concentration near the working face has less effect on the pedestrian roadway could better control the surrounding rock stability of the pedestrian roadway and meet the need of the long-term normal production use. It narrows the width of security coal pillar, increase the coal resources recovery rate and achieve the better economic benefits.

scholarly journals Cutting-Caving Ratio Optimization of Fully Mechanized Caving Mining with Large Mining Height of Extremely Thick Coal Seam

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Kai Wang ◽  
Tong Zhao ◽  
Kaan Yetilmezsoy ◽  
Xiaoqiang Zhang
Keyword(s):  
Coal Seam ◽  
Influencing Factors ◽  
Recovery Rate ◽  
Engineering Application ◽  
Thick Coal Seam ◽  
Coal Wall ◽  
Large Mining Height ◽  
Cutting Height ◽  
The Relationship ◽  
Mining Height

Serious rib spalling and low recovery rate problems caused by the poor top-coal caving property (TCCP) were investigated in fully mechanized caving mining with large mining height (FMCMLMH) of extremely thick coal seam. For this aim, theoretical calculation, numerical simulation, and engineering application were applied to study the reasonable cutting-caving ratio under the influence of different factors. The calculation formula of reasonable cutting height in FMCMLMH was obtained, and effective factors were determined. Moreover, Ft (the top-coal yield failure coefficient) and Fw (the coal wall yield failure coefficient) were defined, and each factor was fitted by using a linear regression equation. The minimum Ft of fully fractured top coal was 0.6, and the main influencing factors were buried depth and Protodyakonov coefficient. The maximum Fw of the stable coal wall was 1.5, and the main influencing factors were buried depth and cutting height. According to the relationship between coal wall stability and recovery rate, the relationship between coal seam strength and top-coal thickness at different cutting heights was obtained, and the mining zone was divided into four subzones. Engineering application showed that the optimal cutting height of Xiegou Coal Mine was 4 m, the cutting-caving ratio was 1 : 2.75, and the recovery rate could reach more than 85%, which was the most reasonable.

scholarly journals Environmental Regulation Intensity, Carbon Footprint and Green Total Factor Productivity of Manufacturing Industries

2022 ◽  
Vol 19 (1) ◽  
pp. 553
Author(s):  
Lei Wang ◽  
Yu Yan
Keyword(s):  
Environmental Regulation ◽  
Total Factor Productivity ◽  
Carbon Footprint ◽  
Manufacturing Industry ◽  
Economic Benefits ◽  
Manufacturing Industries ◽  
Green Economy ◽  
Chinese Government ◽  
Factor Productivity ◽  
The Impact

In terms of the development of the manufacturing industry, the Chinese government has carried out environmental regulations and set up production standards for related industries. This is an environmentally-friendly and economic action, which is also in line with the requirements of building a green economy for China. Meanwhile, whether from the micro regulatory measures or the macro government policies, carbon emission is an inevitable problem in the study of environmental problems. This paper will explore the impact of environmental regulation on the green economy based on carbon emissions and study the optimal environment regulation intensity that relates to a direct carbon footprint under the maximum green economic benefits. A SBM-MALMQUIST model is established to measure the green total factor productivity according to 27 Chinese manufacturing industries through the MAXDEA software. It is found that the intensity of environmental regulation has a significant impact on green total factor productivity, and direct carbon footprint also exhibits a partial intermediary effect, participating in the mechanism that affects green total factor productivity. Combined with the industrial characteristics and the above research results, this paper puts forward the adjustment strategy of reasonable environmental regulation for the manufacturing industry, which conforms to the national policy guidance, and will be beneficial in promoting the economic development of the green manufacturing industry.

scholarly journals Increasing the comprehensive economic benefits of farmland with Even-lighting Agrivoltaic Systems

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254482
Author(s):  
Jianan Zheng ◽  
Shoudong Meng ◽  
Xinyu Zhang ◽  
Honglong Zhao ◽  
Xiaolong Ning ◽  
...  
Keyword(s):  
Electricity Generation ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Glass Plate ◽  
Clean Energy ◽  
Economic Benefits ◽  
Natural State ◽  
Nitrate Content ◽  
Chinese Government ◽  
New Ideas

Agrivoltaic combines crop planting and electricity generation on the same land, it is considered as an opportunity to resolve the competition for land use between food and energy production. In addition to growing crops, farmers can gain electricity with the installation of agrivoltaic systems on their farmland. They can use this clean energy for agricultural production or sell it for extra income. The Chinese government considers it an important strategy for “Targeted Poverty Alleviation”. However, current methods of agrivoltaic provide uneven and low irradiance for crops, which usually results in reduced yield and low quality. In this study, an improved agrivoltaic system with a grooved glass plate has been designed, manufactured, and investigated, called Even-lighting Agrivoltaic System (EAS). Two experiments were conducted to test the effectiveness of the improvement. We measured the crops’ light environment, the crop growth process, the crop yield and quality, the electricity generation, and calculated the Land Equivalent Ratio (LER) as well as the comprehensive economic benefits on the farmland per hectare. Under the EAS, crops grew fast and the yield was similar or better than that under the natural state. By adding supplementary LED lamps into the EAS, the soluble sugar content of lettuce increased by 72.14% and the nitrate content of lettuce decreased by 21.51%. The average LER of the EAS for common vegetables was 1.64 as demonstrated in this work. Comprehensive economic benefits outperform the installation and maintenance costs, thus, the EAS can increase farmers’ income by an average of 5.14 times. The EAS provides new ideas and directions for the future development of agrivoltaic.

Sign in / Sign up

Export Citation Format

Share Document