Destruction of coal seams during mining by dredging machines

2021 ◽  
Author(s):  
Vladimir Linnik
Keyword(s):  
Coal Mining ◽  
Physical Interpretation ◽  
Underground Mining ◽  
Practical Importance ◽  
Cutting Tools ◽  
Operating Conditions ◽  
Coal Seams ◽  
Failure Patterns ◽  
New Energy ◽  
Scientific Substantiation

The monograph is devoted to the issues of scientific substantiation of ways to improve the efficiency of the functioning of the executive bodies of coal mining machines used in the underground mining of coal seams, which are of great practical importance. The results of studies on the reliability of destructive organs are new in the formulation and not previously published in the monograph format. A model is described and a physical interpretation of the failure patterns of auger assemblies and elements is given, methods for assessing the reliability and efficiency of using augers and cutting tools for specific operating conditions using traditional probabilistic and new energy approaches are proposed. It is addressed to engineering and technical workers of design institutions, factories and mines engaged in the design and operation of cleaning combines and plows.

Development of the properties of adaptability of the support sections of treatment complexes to variable mining and geological conditions

2021 ◽  
Vol 326 ◽  
pp. 00024
Author(s):  
Vasilisa Teremetskaya ◽  
Viktor Gabov
Keyword(s):  
Coal Mining ◽  
High Performance ◽  
Operating Conditions ◽  
Underground Coal Mining ◽  
Coal Seams ◽  
Functional Capabilities ◽  
Geological Conditions ◽  
Wide Range ◽  
Favorable Conditions ◽  
Working Out

In modern conditions, intensive underground coal mining is provided, as a rule by working out the dredging sections of coal seams with long cleaning faces using high-performance mechanized complexes. They consist of a dredging machine, a conveyor and a set of sections of mobile mechanized support (SMS). SMS, supporting the roof, controlling the mountain pressure (MP) and protecting the bottom-hole space, provide conditions in complex mechanized treatment faces (CMTF) for efficient and safe coal mining. However, the potential capabilities of modern complexes significantly exceed the values of efficiency indicators achieved when using them in operating conditions. One of the reasons for this situation is the insufficient adaptability of the SMS to the mining and geological conditions (MGC) changing in a wide range as the excavation sites are worked out. Therefore, at present, studies of the possibility of developing the properties of adaptivity (kinematic, power, contact, technological) of the SMS to the MGC variables are relevant. Their results will contribute to the expansion of the functional capabilities of the SMS to maintain favorable conditions in complex mechanized treatment faces for the effective operation of the mechanized treatment complex (MTC) in variable mining and geological conditions.

Substantiation of safe underground mining in series of coal seams under hydraulic fill

2018 ◽  
Vol 8 ◽  
pp. 217-226
Author(s):  
Yu.I. Kutepov ◽  
◽  
A.S. Mironov ◽  
Yu.Yu. Kutepov ◽  
M.V. Sablin ◽  
...  
Keyword(s):  
Underground Mining ◽  
Coal Seams ◽  
Hydraulic Fill ◽  
In Series

Optimizing Shearer Web Width in Underground Mining of Gently Dipping Methane-Bearing Coal Seams

2019 ◽  
Vol 55 (6) ◽  
pp. 938-945
Author(s):  
A. A. Ordin ◽  
A. M. Timoshenko ◽  
D. V. Botvenko
Keyword(s):  
Underground Mining ◽  
Coal Seams

scholarly journals Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3193
Author(s):  
Ana L. Santos ◽  
Maria-João Cebola ◽  
Diogo M. F. Santos
Keyword(s):  
Energy Content ◽  
Water Electrolysis ◽  
High Energy ◽  
Operating Conditions ◽  
Energy Sources ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water ◽  
New Energy ◽  
Recent Developments ◽  
Cell Components

Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. This review examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis. This process is far from being new, but research shows that there is still plenty of room for improvement. The efficiency of an electrolyzer mainly relates to the overpotential and resistances in the cell. This work shows that the path to better electrolyzer efficiency is through the optimization of the cell components and operating conditions. Following a brief introduction to the thermodynamics and kinetics of water electrolysis, the most recent developments on several parameters (e.g., electrocatalysts, electrolyte composition, separator, interelectrode distance) are highlighted.

Modeling of the stress-state longwall face during coal mining with the technology of roof management complete drop and stowing

2020 ◽  
pp. 99-106
Author(s):  
I. E. Mazina ◽  
A. A. Stel’makhov ◽  
L. F. Mullagalieva
Keyword(s):  
Coal Mining ◽  
Strain State ◽  
Underground Mining ◽  
Negative Impact ◽  
Hydrological Regime ◽  
Coal Bed ◽  
Stress Strain ◽  
Environmental Friendliness ◽  
Modeling And Analysis ◽  
Stress Strain State

Underground mining of coal deposits has a negative impact on all components of the environment. When developing a coal deposit, it is coal mining technology that determines the scale and consequences of the negative impact. Changes in the stress-strain state of the geo-environment can lead to a violation of the hydrological regime, increased gas emission from the host rocks, the initiation of gas-dynamic processes. Choice of roofing management technology - as a geotechnological method of natural and technical system management determines the environmental friendliness of coal mining and creates safety conditions. The article deals with the technology of roofing control during coal production. For this purpose mathematical modeling and analysis of stress-strain state of the bottomhole part of the coal bed for the conditions of S.M. Kirov is performed. As a result of modeling, two technologies of roof control were analyzed - complete caving and stowing. For the worked out clearing leaves filled with either caving rocks or stowing material, there are characteristic unloading zones in the massif to be worked and overworked, as well as pressure reference zones, which fall on the parts of the pillars associated with the lava. It was found out that the application of the stowing technology creates conditions for minimization of gravitational stresses in the geoenvironment, as well as significantly reduces the potential energy of form change.

scholarly journals Methane Content Estimation in DuongHuy Coal Mine

2018 ◽  
Vol 35 ◽  
pp. 01005 ◽  
Author(s):  
Van Thinh Nguyen ◽  
Waldemar Mijał ◽  
Vu Chi Dang ◽  
Thi Tuyet Mai Nguyen
Keyword(s):  
Experimental Data ◽  
Coal Mining ◽  
Coal Mine ◽  
Coal Mines ◽  
Methane Content ◽  
Underground Coal Mining ◽  
Coal Seams ◽  
Underground Coal Mine ◽  
Different Depths ◽  
Quang Ninh

Methane hazard has always been considered for underground coal mining as it can lead to methane explosion. In Quang Ninh province, several coal mines such as Mạo Khe coal mine, Khe Cham coal mine, especially Duong Huy mine that have high methane content. Experimental data to examine contents of methane bearing coal seams at different depths are not similar in Duong coal mine. In order to ensure safety, this report has been undertaken to determine a pattern of changing methane contents of coal seams at different exploitation depths in Duong Huy underground coal mine.

BOREHOLE‐RADAR EXPLORATION IN A COAL SEAM

Geophysics ◽  
1977 ◽  
Vol 42 (6) ◽  
pp. 1254-1257 ◽  
Author(s):  
John C. Cook
Keyword(s):  
Coal Seam ◽  
Practical Importance ◽  
Low Resolution ◽  
Coal Seams ◽  
Australian Society ◽  
Great Practical Importance ◽  
The Third ◽  
Research Organizations ◽  
Borehole Radar ◽  
Experimental Use

The experimental use of “geologic radar” to explore through coal from mined passages underground has already been reported elsewhere (Cook, 1973, 1974). Low‐resolution borehole radar work in salt, a much more favorable medium, has also been reported (Holzer et al., 1972). The purpose of this paper is to report the first known results of borehole radar tests in coal. The exploration of coal seams via boreholes from the surface is potentially a technique of great practical importance. The borehole experiment was performed in conjunction with a month‐long program of radar tests in Australian collieries and quarries performed under the sponsorship of the third ICOGEO and supported by several Australian mining and research organizations. A report on that program is expected to appear in the Bulletin of the Australian Society of Exploration Geophysicists some time during 1977.

Directionally Independent Failure Prediction of End-Milling Tools During Pocketing Maneuvers

2007 ◽  
Vol 129 (4) ◽  
pp. 770-779 ◽  
Author(s):  
Christopher A. Suprock ◽  
Joseph J. Piazza ◽  
John T. Roth
Keyword(s):  
Discrete Cosine Transform ◽  
End Milling ◽  
Cutting Tools ◽  
Primary Component ◽  
Operating Conditions ◽  
Frequency Method ◽  
Cosine Transform ◽  
Impending Fracture ◽  
Triaxial Dynamometer ◽  
Acceleration Signals

Tracking the health of cutting tools under typical wear conditions is advantageous to the speed and efficiency of manufacturing processes. Existing techniques monitor tool performance through analyzing force or acceleration signals whereby prognoses are made from a single sensor type. This work proposes to enhance the spectral output of autoregressive (AR) models by combining triaxial accelerometer and triaxial dynamometer signals. Through parallel processing of force and acceleration signals using single six degree of freedom modeling, greater spectral resolution is achieved. Two entirely independent methods of tracking the tool wear are developed and contrasted. First, using the discrete cosine transform, primary component analysis will be applied to the spectral output of each AR auto and cross spectrum (Method 1). Each discrete cosine transform of the six-dimensional spectral data is analyzed to determine the magnitude of the critical (primary) variance energy component of the respective spectrum. The eigenvalues of these selected spectral energies are then observed for trends toward failure. The second method involves monitoring the eigenvalues of the spectral matrices centered at the toothpass frequency (Method 2). The results of the two methodologies are compared. Through the use of the eigenvalue method, it is shown that, for straight and pocketing maneuvers, both methods successfully track the condition of the tool using statistical thresholding. The techniques developed in this work are shown to be robust by multiple life tests conducted on different machine platforms with different operating conditions. Both techniques successfully identify impending fracture or meltdown due to wear, providing sufficient time to remove the tools before failure is realized.

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