Field Measurement and Numerical Modelling Study on Mining-Induced Subsidence in a Typical Underground Mining Area of Northwestern China

Advances in Civil Engineering ◽

10.1155/2021/5599925 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Kai Zhang ◽

Lu Bai ◽

Pengfei Wang ◽

Zhuang Zhu

Keyword(s):

Field Measurement ◽

Underground Mining ◽

Numerical Study ◽

Coal Mines ◽

Ground Surface ◽

Northwest China ◽

Mining Activity ◽

Longwall Panel ◽

Underground Coal Mines ◽

The Future

Mining-induced subsidence is a great concern for environmental protection in underground mining areas in China and all over the world. In view of the fact that the research on land degradation above underground coal mines are completely or partially independent of coal mining activity and the fact that the mechanism behind mining-induced subsidence has not been well understood, this study presents a field measurement and numerical study of mining-induced subsidence with respect to mining activity of three adjacent longwall panels in a coal mine in Northwest China. This study shows that surface subsidence lags far behind panel extraction or mining activity. The profiles of ground surface are dominated and manifested by the subsurface strata structures. The subsidence influence throughout the whole length of a longwall panel varies. Stability of strata structures within overburden before the final subsidence controls the stability of ground surface land. Chain pillars of 20 m between panels of 240 m wide with cover depth of 600 m have been crushed in the gob and do not have any function in supporting the overburden strata. The final subsidence of the three adjacent panels is far to come in the future and the land reuse above underground coal mines should be carefully planned by making sure that the gob is completely compacted or no potential secondary subsidence occurs in the future.

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Chamber Relative to the Previously Extracted Longwall Panel

E3S Web of Conferences ◽

10.1051/e3sconf/202017401005 ◽

2020 ◽

Vol 174 ◽

pp. 01005

Author(s):

Inna Ermakova ◽

Vyacheslav Fedusov

Keyword(s):

Coal Mines ◽

Longwall Face ◽

Face Width ◽

Longwall Panel ◽

Underground Coal Mines

Longwall salvage activities at JSC SUEK-Kuzbass underground coal mines may experience unforeseen delays. To determine the causes of the delays in the salvage activities, we have considered various factors. Firstly, we have analyzed the effect of the longwall face width on the duration of salvage activities. We have proved that this factor does not have a statistically significant effect on the duration of salvage activities. We have established that the duration of the salvage activities is determined by the location of the salvage chambers relative to the pillar and the previously extracted panel. In the event that contiguous previously extracted panel is located near the salvage chamber, the salvage time is doubled on average.

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Analyzing and identifying the limits of 660V grid parameters to ensure electrical safety in underground coal mines

Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu ◽

10.33271/nvngu/2021-6/101 ◽

2021 ◽

pp. 101-106

Author(s):

Le Xuan Thanh ◽

Ho Viet Bun

Keyword(s):

Leakage Current ◽

Underground Mining ◽

Coal Mines ◽

Electrical Safety ◽

Explosion Safety ◽

Leakage Currents ◽

Electric System ◽

Earth Fault ◽

Operation Conditions ◽

Underground Coal Mines

Purpose. To study the relation between leakage current and time, then to identify some limits of grid parameters to ensure electrical safety as well as explosion safety corresponding to all operating modes of leakage relay in Vietnam underground mines. Methodology. In underground coal mines of Vietnam, 660 V grids are characterized by ungrounded neutral point electric system. They require very serious and strict operation conditions including electrical safety and explosion safety. In daily operation, the earth leakage currents (earth fault currents) must be lower than the allowance limit. However, when utilizing many new power electronic devices such as variable speed drive (VSD), the quantity of connected equipment changes due to the change in capacitance current. After measuring the grid parameters, leakage currents are computed in terms of 3 compensating levels of earth fault relays. The resulting values of currents are used to build up limit curves. Findings. Curves of the graphs present the relation between the leakage current and the length of transmission cables associated with various connecting equipment. The curves may be used to operate the electric system safely and effectively. Originality. The proposed equations and simulation in Matlab may be applied to all underground mining grids with different input parameters. Practical value. Operating curves of the graphs are used to identify the most suitable grids parameters which could ensure electrical safety (keeping the leakage current within the allowance limits). It could help operators or technicians optimize the structure of grid and ensure its safety.

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Numerical study on water-jet cutting technique applied in underground coal mines

Numerical Methods in Geotechnical Engineering IX ◽

10.1201/9781351003629-170 ◽

2018 ◽

pp. 1353-1360

Author(s):

W.L. Gong ◽

Y.X. Sun ◽

X. Goa ◽

J.L. Feng ◽

Z.H. Li ◽

...

Keyword(s):

Numerical Study ◽

Coal Mines ◽

Water Jet ◽

Water Jet Cutting ◽

Underground Coal Mines

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THE FUTURE OF MINE-WATER DISCHARGES FROM UNDERGROUND COAL MINES OF THE PITTSBURGH COAL BASIN, WV-PA

Journal American Society of Mining and Reclamation ◽

10.21000/jasmr04010518 ◽

2004 ◽

Vol 2004 (1) ◽

pp. 518-529 ◽

Cited By ~ 1

Author(s):

Joseph J. Donovan ◽

◽

Bruce R. Leavitt

Keyword(s):

Mine Water ◽

Coal Mines ◽

Coal Basin ◽

Underground Coal Mines ◽

The Future

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Application of a Small Baseline Subset Time Series Method with Atmospheric Correction in Monitoring Results of Mining Activity on Ground Surface and in Detecting Induced Seismic Events

Remote Sensing ◽

10.3390/rs11091008 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1008 ◽

Cited By ~ 6

Author(s):

Wojciech Milczarek

Keyword(s):

Time Series ◽

Underground Mining ◽

Ground Surface ◽

Mining Activity ◽

Seismic Events ◽

Atmospheric Delay ◽

Small Baseline Subset ◽

Sar Data ◽

Small Baseline ◽

Surface Changes

The article presents the results of applying a Small Baseline Subset (SBAS) method to the monitoring of the influence of underground mining exploitation on terrain surface. Calculations were performed on the basis of two large SAR data sets. Calculations of time series additionally employed the Tymofyeyeva and Fialko empirical method for estimating atmospheric delay. A series of test calculations allowed verifying the potential of the method. The SBAS calculations were based on theoretical data prepared with the use of the Mogi model. This approach allowed simulating both underground mining exploitation and induced tremors. The results indicate that the model is useful in detecting sudden ground surface deformations. In such a situation, the image of a tremor can be observed in the atmospheric component. The actual data used in the analysis covered a region of underground copper ore extraction in southwest Poland. The calculations were based on SAR data obtained from the Sentinel 1A/B satellites, for the period between the end of 2014 and May 2018, from paths 22 and 73. In both cases, the total number of images exceeded 120. They served to calculate over 420 interferograms for each set. The results of ground surface displacements allowed precise identification of areas affected by underground mining activity. Over the acquisition period of six days, sufficient amount of SAR data was obtained to precisely monitor surface changes in the analyzed area. The employed empirical atmospheric delay reduction method was demonstrated to enable the detection of sudden ground surface changes due to mining tremors. This feature makes the method useful in detecting induced seismic events in areas characterized by intensive mining activity. It allows determining tremor locations in cases when acquisition dates are greater than the optimal value of 6–12 days (in the case of Sentinel 1A/B).

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Improvement of production control of coal mining enterprises with underground mining method

E3S Web of Conferences ◽

10.1051/e3sconf/202130301017 ◽

2021 ◽

Vol 303 ◽

pp. 01017

Author(s):

Tatyana Tyuleneva

Keyword(s):

Coal Mining ◽

Production Control ◽

Underground Mining ◽

Coal Mines ◽

Underground Coal Mining ◽

Safety Requirements ◽

Production Control System ◽

Production Safety ◽

Foreign Countries ◽

Underground Coal Mines

Production safety is one of the problems of competitiveness of underground mining enterprises, one manifestation of which is the reduction and minimization of the number of accidents and incidents of personal injury or even death. To solve this problem, it is necessary to improve the system of production control of coal mines in order to eliminate these factors. Relative indicators of accidents and injuries at underground coal mines of Russia in comparison with the average indicators are considered, and also importance of the human factor in the occurrence of dangerous production situations and the evaluation of their causes and effects are revealed. In addition, the article considers the most common violations of safety requirements for underground coal mining, analyzes the experience of foreign countries in improving the production control system, assesses the possibility of its application for improving production control at Russian coal mines, and determines main areas for implementing a risk-based approach at coal mining enterprises.

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Whole-Body Vibration Exposures in Undeground Coal Mining Operations

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/1541931213601210 ◽

2016 ◽

Vol 60 (1) ◽

pp. 914-918

Author(s):

D. Lynas ◽

R. Burgess-Limerick

Keyword(s):

Coal Mining ◽

Underground Mining ◽

Coal Mines ◽

Whole Body Vibration ◽

Electrical Equipment ◽

Whole Body ◽

Mining Equipment ◽

Mining Operations ◽

Body Vibration ◽

Underground Coal Mines

Studies conducted on surface coal mining equipment have identified whole-body vibration as a significant hazard. Operators of underground mobile equipment, particularly shuttle cars and transport vehicles, are likely to be exposed to significant levels of whole-body vibration. To date, measuring whole-body vibration from underground mining mobile equipment has been difficult due to the strict guidelines governing the use of electrical equipment in underground mines. This paper presents data obtained from two low-methane coal mines using an iOS application installed on iPod Touch devices. The majority of measurements taken from a range of mobile plant and equipment in use at the underground coal mines exceeded the ISO2631.1 Health Guidance Caution Zone. Further investigations are being undertaken to develop a thorough understanding of whole-body vibration exposures to which operators of mobile equipment used in underground coal mines are exposed and the opportunities for application of this information to assist mine site safety, health and risk management processes.

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