نتایج جستجو برای: coal mines

تعداد نتایج: 37421  

Journal: :زمین شناسی اقتصادی 0
طاهره ربانی نادر تقی پور رضا اهری پور

introduction maceral is a term to introduce organic components visible under a microscope (stopes, 1935). the physical and chemical characteristics of macerals such as elemental composition, moisture content, hardness, density and petrographic characteristics differ. the differences in the physical and chemical characteristics of macerals are reflected in their industrial behavior.(parkash, 198...

Journal: :The Science of the total environment 2006
Mingshi Wang Baoshan Zheng Binbin Wang Shehong Li Daishe Wu Jun Hu

The arsenic concentrations in 297 coal samples were collected from the main coal-mines of 26 provinces in China were determined by molybdenum blue coloration method. These samples were collected from coals that vary widely in coal rank and coal-forming periods from the five main coal-bearing regions in China. Arsenic content in Chinese coals range between 0.24 to 71 mg/kg. The mean of the conce...

Journal: :iranian journal of public health 0
jizu li institute of economic management, taiyuan university of technology, p.r. china. yuejiao li institute of economic management, taiyuan university of technology, p.r. china. xiaoguang liu institute of economic management, taiyuan university of technology, p.r. china

background : in china, over 80% of all work-related deaths in the mining industry occur in coal mines and human factors constitute 85% of the direct causes of coal mine accidents, which indicates that significant shortcomings cur-rently exist in the safety behavior management of chinese coal mine workers. we aimed to verify the impact of human psychological behavior in coal mine accidents syste...

2003
Michael P. Evans

and ECA coal analysers have been used to control sorting and blending operations at coal mines, power plants and coal terminals. In sorting operations, the analyser results are used to sort coal into piles, bins or silos based on the measured quality. Coals can be sorted by the ash, sulphur, moisture, heating value, or by combinations of these. Sorting can be used to allow low-ash coals to bypa...

2000
Thomas M. Stoker Ernst R. Berndt A. Denny Ellerman Susanne M. Schennach

We analyze labor productivity in coal mining in the United States using indices of productivity change associated with the concepts of panel data modeling. This approach is valuable when there is extensive heterogeneity in production units, as with coal mines. We ̄nd substantial returns to scale for coal mining in all geographical regions, and ̄nd that smooth technical progress is exhibited by ...

Abbas Esmaeilnia Shirvani Hossein Ghafourian

Coal with low ash content has an important role in the coal and steel industry. There are different methods to measure the ash content. The conventional method which is used in most coal mines of Iran, is to burn the coal and measure the remaining ash. A new method has been recently developed at Nuclear Research Center (NRC) of Iran, Which works on the basis of the absorption of the dual en...

2015
P. Kaminski

Nowadays, one of the main tasks of Ukrainian coal industry is increasing labour productivity by means of complex mechanization and automatization of mining operations with usage of modern equipment. The best example is implementation of modern plow complexes on Western Donbas mines, PJSC “DTEK Pavlogradvugillia”. Currently, plowing is one of perspective directions of coal extraction development...

2004

Ukraine has substantial reserves of methane resident in underground coal seams and surrounding rock strata that, if captured, would constitute a valuable energy resource. During 2002, Ukraine consumed 78 billion cubic meters (bcm) of natural gas and produced domestically only 18 bcm. Ukraine receives approximately 30 bcm per year as a transit fee for the use of their pipeline system to transpor...

Journal: :The Science of the total environment 2002
Bin He Lina Liang Guibin Jiang

The contents of arsenic and selenium in 33 coals collected from the main coal mines in northeastern, northern and eastern China were determined by flow injection-hydride generation and non-dispersion atomic fluorescence spectrometry (HGAFS). The concentrations of As in the northeast region are relatively higher with the values > 100 microg g(-1); in the east they are lower with values < 100 mic...

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