Longwall Face Crew Selection With Respect to Stochastic Character of the Production Process – Part 2 – Calculation Example / Wyznaczanie obsady przodka ścianowego z uwzględnieniem stochastycznego charakteru procesu produkcyjnego cz. 2 – przykład obliczeniowy

2013 ◽  
Vol 58 (1) ◽  
pp. 227-240
Author(s):  
Ryszard Snopkowski ◽  
Marta Sukiennik
Keyword(s):  
Production Process ◽  
Coal Mine ◽  
Selection Method ◽  
Longwall Face ◽  
Final Part ◽  
Hard Coal ◽  
Graphical Interpretation ◽  
Cut And Fill

A calculation example of the longwall face crew selection, including taking under consideration stochastic character of the production process is presented in this study. On the basis of observation of duration of activities realized in the hard coal mine longwall face with use of the roof cut and fill system, the calculations with use of the proposed crew selection method have been executed. The method in question takes into consideration stochastic character of the realized production process (Snopkowski & Sukiennik, 2012). In the final part of this study, graphical interpretation of the executed calculations has been presented.

Microbial Methane Formation from Hard Coal and Timber in an Abandoned Coal Mine

2008 ◽  
Vol 25 (6) ◽  
pp. 315-321 ◽  
Author(s):  
Martin Krüger ◽  
Sabrina Beckmann ◽  
Bert Engelen ◽  
Thomas Thielemann ◽  
Bernhard Cramer ◽  
...  
Keyword(s):  
Coal Mine ◽  
Hard Coal ◽  
Methane Formation ◽  
Abandoned Coal Mine

scholarly journals Stress Distribution Around Mechanized Longwall Face at Deep Mining in Quang Ninh Underground Coal Mine

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Manh Tung BUI ◽  
Tien Dung LE ◽  
Trong Hung VO
Keyword(s):  
Stress Distribution ◽  
Sea Level ◽  
Coal Mine ◽  
Coal Mines ◽  
Longwall Face ◽  
Geological Condition ◽  
Deep Mining ◽  
Roof Fall ◽  
The Impact ◽  
Quang Ninh

Quang Ninh underground coal mines are currently in the phase of finishing up the mineralreserves located near the surface. Also, in this phase, a number of coal mines have opened and preparednew mine sites for the extraction of the reserves at greater depth. Several mines have mined at -350 mdepth and are driving opening excavations at -500 m depth below sea level. The mining at greater depthfaces many difficulties, such as a significant increase in support and excavation pressures. The longwallface pressure is mostly manifested in great magnitude that causes support overloaded and jumped andface spall/roof fall. This paper, based on the geological condition of the Seam 11 Ha Lam coal mine,uses the numerical program UDEC for studying the impact of mining depth on stress distribution aroundthe longwall face. The results show that the deeper the mining is, the greater the plastic deformationzone is. The peak front abutment stress moves closer to the coal wall, mainly concentrating on theimmediate roof and top coal. The top coal is greatly broken, and its bearing capacity is decreased. Somesolutions to the stability of roof strata are proposed, and a proper working resistance of support isdetermined. Additionally, the paper suggests that the starting depth for deep mining in Quang Ninhunderground coal mines should be -350 m below sea level.

scholarly journals Failure Mechanisms and the Control of a Longwall Face with a Large Mining Height within a Shallow-Buried Coal Seam

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Haijun Wang ◽  
Yingjie Liu ◽  
Yuesong Tang ◽  
Hao Gong ◽  
Guoliang Xu
Keyword(s):  
Tensile Stress ◽  
Coal Mine ◽  
Horizontal Displacement ◽  
Longwall Face ◽  
Mining Equipment ◽  
Coal Seams ◽  
Increasing Trend ◽  
Support Force ◽  
Coal Wall ◽  
Mining Height

The capabilities of mining equipment and technology in China have been improving rapidly in recent years. Correspondingly, in the western part of the country, the mining heights of longwall faces in shallow-buried coal seams have shown an increasing trend, resulting in enhanced mining efficiency. However, the problems associated with the possible failure of the coal wall then increase and remain a serious difficulty, restricting safe and efficient mining operations. In the present study, the 12401 longwall face of the Shangwan Coal Mine, Inner Mongolia, China, with a mining height of 8.8 m, is taken as an example to study the mechanisms underlying failure phenomena of coal walls and their control methods. Our results show that the failure region inward of the longwall face is small in shallow-buried coal seams, and the damage degree of the exposed coal wall is low. The medium and higher sections of the coal wall display a dynamic failure mode, while the broken coal blocks, given their initial speed, threaten the safety of coal miners. A mechanical model was developed, from which the conditions for tensile failure and structural instability are deduced. Horizontal displacement in the lower part of the coal wall is small, where no tensile stress emerges. On the other hand, in the intermediate and higher parts of the coal wall, horizontal displacement is relatively large. In addition, tensile stress increases first with increasing distance from the floor and then decreases to zero. Experiments using physical models representing different mining heights have been carried out and showed that the horizontal displacement increases from 6 to 12 mm and load-bearing capacity decreases from 20 to 7.9 kN when the coal wall increases in height from 3 to 9 m. Furthermore, failure depth and failure height show an increasing trend. It is therefore proposed that a large initial support force, large maximum support force, large support stiffness, and large support height of a coal wall-protecting guard are required for the improved stability of high coal walls, which operate well in the Shangwan coal mine.

scholarly journals Quantifying CH<sub>4</sub> emissions from hard coal mines using mobile sun-viewing Fourier transform spectrometry

2019 ◽  
Vol 12 (10) ◽  
pp. 5217-5230 ◽  
Author(s):  
Andreas Luther ◽  
Ralph Kleinschek ◽  
Leon Scheidweiler ◽  
Sara Defratyka ◽  
Mila Stanisavljevic ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Coal Mine ◽  
Mine Ventilation ◽  
Hard Coal ◽  
Spatial And Temporal Variability ◽  
The European Union ◽  
Cross Sectional ◽  
Ch4 Emissions ◽  
Fourier Transform Spectrometry ◽  
Relative Errors

Abstract. Methane (CH4) emissions from coal production amount to roughly one-third of European anthropogenic CH4 emissions in the atmosphere. Poland is the largest hard coal producer in the European Union with the Polish side of the Upper Silesian Coal Basin (USCB) as the main part of it. Emission estimates for CH4 from the USCB for individual coal mine ventilation shafts range between 0.03 and 20 kt a−1, amounting to a basin total of roughly 440 kt a−1 according to the European Pollutant Release and Transfer Register (E-PRTR, http://prtr.ec.europa.eu/, 2014). We mounted a ground-based, portable, sun-viewing FTS (Fourier transform spectrometer) on a truck for sampling coal mine ventilation plumes by driving cross-sectional stop-and-go patterns at 1 to 3 km from the exhaust shafts. Several of these transects allowed for estimation of CH4 emissions based on the observed enhancements of the column-averaged dry-air mole fractions of methane (XCH4) using a mass balance approach. Our resulting emission estimates range from 6±1 kt a−1 for a single shaft up to 109±33 kt a−1 for a subregion of the USCB, which is in broad agreement with the E-PRTR reports. Three wind lidars were deployed in the larger USCB region providing ancillary information about spatial and temporal variability of wind and turbulence in the atmospheric boundary layer. Sensitivity studies show that, despite drawing from the three wind lidars, the uncertainty of the local wind dominates the uncertainty of the emission estimates, by far exceeding errors related to the XCH4 measurements themselves. Wind-related relative errors on the emission estimates typically amount to 20 %.

Ocena Właściwości Technogenicznych Utworów Glebowych Technosols Zawierających Siarczki Żelaza / Assessment of Properties of Technogenic Soils Technosols Containing Iron Sulfides

2012 ◽  
Vol 63 (3) ◽  
pp. 37-42 ◽  
Author(s):  
Łukasz Uzarowicz ◽  
Alina Maciejewska
Keyword(s):  
Heavy Metals ◽  
Coal Mine ◽  
Mine Tailings ◽  
Hard Coal ◽  
Iron Sulfides ◽  
Radioactive Elements ◽  
Rock Fragments ◽  
Technogenic Soils ◽  
Strong Acidity

Abstract Technogenic soils (Technosols) developed from mine tailings containing iron sulfides occurring in the area of the abandoned .Siersza. hard coal mine in Trzebinia and the abandoned .Staszic. pyrite mine in Rudki were investigated in order to assess their properties. The study revealed that the most adverse properties of the technogenic soils investigated are: strong acidity (pH below 3), the presence of large amounts of rock fragments containing unweathered sulfides, as well as the occurrence of heavy metals (e.g. Pb, As, and Tl) and radioactive elements (U and Th). All these properties should be taken into account during management of the studied mine tailings.

Research on Underground Coal Mine Production Process Analysis and Informatization

2010 ◽  
Vol 171-172 ◽  
pp. 278-282 ◽  
Author(s):  
Jin Feng Wang ◽  
Li Jie Feng ◽  
Zhen Zhao ◽  
Hua Jie Yu
Keyword(s):  
Information System ◽  
Production Process ◽  
Coal Mine ◽  
Process Analysis ◽  
Underground Coal Mine ◽  
Continuous Type ◽  
Production Processes ◽  
Mine Production ◽  
Discrete Type

This article analyzes the characteristics of underground coal mine production process, and compares underground coal mine production process with discrete type and continuous type production processes. On this basis, it investigates the construction and implementation countermeasures on underground coal mine information system.

scholarly journals Failure Behavior and Energy Storage and Release of Hard Coal under Different Static and Dynamic Loading States

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
XianJie Hao ◽  
GuangYao Pan ◽  
Chaoxing Ma ◽  
Yingnan Wei ◽  
Zeyu Chen
Keyword(s):  
Dynamic Loading ◽  
Coal Mine ◽  
Static Loading ◽  
Dynamic Compression ◽  
Hard Coal ◽  
Failure Behavior ◽  
Static Compression ◽  
Energy Rate ◽  
Energy Accumulation ◽  
Static Tensile

The study of the energy accumulation and rate of release in hard coal under dynamic, static, and coupled dynamic-static loading and its failure mode is of significance when studying the mechanism underpinning coal mine dynamic disasters such as rock burst, coal, and gas outburst. In this paper, four experimental methods (uniaxial compression, Brazilian splitting, and coupled dynamic-static tensile and coupled dynamic-static compression) were used to analyze the energy accumulation, energy rate of release, and failure modes of this type of hard coal under different loading conditions. It was concluded that (1) the energy accumulation and rate of releases of this type of hard coal under static compression are 17.63–179.90 times and 18.57–13157.89 times those under static tension; the energy accumulation and rate of releases in dynamic compression are 2.11–248.53 and 0.23–48 times those under dynamic tension, respectively. (2) During dynamic loading, the ratio of compressive energy accumulation to tensile energy accumulation is reduced by 1.6 times compared with static loading, and the ratio of compressive energy release to tensile energy rate of release is decreased by 363.84 times compared with static loading. (3) The energy accumulation and rate of releases of this type of hard coal for dynamic tensile are, respectively, 2.64–17.42 and 1.07–5.26 times those under static tensile load; the energy accumulation under dynamic compression is greater than that under static compression, being 0.24–15.04 times that under static compressive, but the energy rate of release under dynamic compression is 0.0003–0.56 times that under static compression. (4) The greater the prepeak energy accumulation, the greater the degree of damage of the coal sample at each stage, and also the higher the degree of fragmentation after the failure. The research results play an important guiding role in further understanding the mechanism of coal mine dynamic disasters.

scholarly journals A Study of the Laws of Abnormal Gas Emissions and the Stability Controls for Coal Mine Walls in Deeply Buried High-Gas Coal Seams

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Anying Yuan ◽  
Hao Hu ◽  
Qiupeng Yuan
Keyword(s):  
Coal Seam ◽  
Water Content ◽  
Coal Mine ◽  
Gas Diffusion ◽  
Hard Coal ◽  
Coal Seams ◽  
Gas Emissions ◽  
Soft Coal ◽  
Pressure Water ◽  
Gas Coal

At the present time, it is considered to be of major significance to study the gas emission law and stability controls of coal bodies in deeply buried high-gas coal seams. For this reason, in view of the specific problems of gas emissions caused by unstable rib spalling in coal mine walls, comprehensive research methods were adopted in this study, in order to conduct an in-depth examination of micropore structure parameters, gas desorption, diffusion laws, and coal stability levels. The results showed that the development degree of the pores above the micropores, as well as the small pores in soft coal seams, was better than those observed in hard coal seams. In addition, the gas outburst phenomenon was found to have more easily formed in the soft coal seams. The coal body of the No. 6 coal seam in the Xieqiao Coal Mine not only provided the conditions for gas adsorption but also provided dominant channels for gas diffusion and migration. The abnormal gas emissions of the No. 6 coal seam were jointly caused by the relatively developed pores above the small holes in the coal body, rib spalling of coal mine walls, and so on. The research results also revealed the evolution law of mechanical characteristics of the No. 6 coal seam under different water content conditions. It was found that the strength levels of the No. 6 coal seam first increased and then decreased with the increase in water content, and the water content level at the maximum strength of the coal seam was determined to be 7.09%. This study put forward a method which combined the water injection technology of long-term static pressure water injections in deep coal mining holes and real-time dynamic pressure water injections in shallower holes. Field experiments were successfully carried out.

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