WorldWideScience

Sample records for brown coal seam

  1. Exploration possibilities of Oligocene brown coal seams in the Vertessomio - Majkpuszta - Orosziany region

    Energy Technology Data Exchange (ETDEWEB)

    Gidai, L.

    1986-01-01

    The history of exploration, the stratigraphic conditions of the Oligocene formations together with the tectonics of the region are discussed. Based on exploration borehole data the expected thickness and distribution of the coal seams are presented. As demonstrated by the isopach lines the depth of the Oligocene coal seams varies between 50 and 300 mm below the surface, i.e. the beds lie somewhat higher than the Eocene coal-bearing strata. For this very reason the region seems to be extractable though the thickness of the coal seams falls behind the Eocene ones.

  2. Geomorphology of coal seam fires

    Science.gov (United States)

    Kuenzer, Claudia; Stracher, Glenn B.

    2012-02-01

    Coal fires occur in underground natural coal seams, in exposed surface seams, and in coal storage or waste piles. The fires ignite through spontaneous combustion or natural or anthropogenic causes. They are reported from China, India, USA, South Africa, Australia, and Russia, as well as many other countries. Coal fires lead to loss of a valuable resource (coal), the emission of greenhouse-relevant and toxic gases, and vegetation deterioration. A dangerous aspect of the fires is the threat to local mines, industries, and settlements through the volume loss underground. Surface collapse in coal fire areas is common. Thus, coal fires are significantly affecting the evolution of the landscape. Based on more than a decade of experience with in situ mapping of coal fire areas worldwide, a general classification system for coal fires is presented. Furthermore, coal seam fire geomorphology is explained in detail. The major landforms associated with, and induced by, these fires are presented. The landforms include manifestations resulting from bedrock surface fracturing, such as fissures, cracks, funnels, vents, and sponges. Further manifestations resulting from surface bedrock subsidence include sinkholes, trenches, depressions, partial surface subsidence, large surface subsidence, and slides. Additional geomorphologic coal fire manifestations include exposed ash layers, pyrometamorphic rocks, and fumarolic minerals. The origin, evolution, and possible future development of these features are explained, and examples from in situ surveys, as well as from high-resolution satellite data analyses, are presented. The geomorphology of coal fires has not been presented in a systematic manner. Knowledge of coal fire geomorphology enables the detection of underground coal fires based on distinct surface manifestations. Furthermore, it allows judgments about the safety of coal fire-affected terrain. Additionally, geomorphologic features are indicators of the burning stage of fires

  3. Roadway failure and support in a coal seam underlying a previously mined coal seam

    Institute of Scientific and Technical Information of China (English)

    Lu Yinlong; Wang Lianguo; Zhang Bei

    2012-01-01

    The influence of an upper,mined coal seam on the stability of rock surrounding a roadway in a lower coal seam is examined.The technical problems of roadway control are discussed based on the geological conditions existing in the Liyazhuang Mine No.2 coal seam.The stress distribution and floor failure in the lower works after mining the upper coal is studied through numerical simulations.The failure mechanism of the roof and walls of a roadway located in the lower coal seam is described.The predicted deformation and failure of the roadway for different distances between the two coal seams are used to design two ways of supporting the lower structure.One is a combined support consisting of anchors with a joist steel tent and a combined anchor truss.A field test of the design was performed to good effect.The results have significance for the design of supports for roadways located in similar conditions.

  4. Induced polarization signature of coal seam fires

    Science.gov (United States)

    Shao, Zhenlu; Revil, André; Mao, Deqiang; Wang, Deming

    2017-03-01

    Coal seam fires are a worldwide disaster of both ecological and economic importance. Their remote detection from the ground surface or using airborne techniques is required for developing efficient strategies to extinguish them. We investigate here the use of time-domain-induced polarization to localize coal seam fires. For laboratory experiments, we first introduce a modified time-domain-induced polarization methodology to quickly acquire and invert the secondary voltage distribution mapped after the shutdown of the primary current. A set of sandbox experiments is conducted in which coal is embedded into humidified sand. Raw coal alone generates significant induced polarization anomalies, above those shown by the sand. Even higher induced polarization anomalies are detected in presence of a coal seam fire. We postulate that the higher chargeability is due to the pyrolysis, which may enhance electronic polarization or the polarization associated with the cation exchange capacity (CEC) of the material. The position of the coal seam fire is well recovered inside the tank by inverting the secondary voltages in term of a source current density distribution. We also collected field data over a recognized coal seam fire in Colorado, USA. A chargeability anomaly (˜800 mV V-1) and a resistivity anomaly (˜1 Ohm m) are observed at the position of the coal seam fire. We propose a normalized burning front index (a scaled normalized chargeability) to image and localize, without ambiguity, the position of the coal seam fire in the subsurface. The 3-D reconstructed target is located below a negative self-potential anomaly (similarly to what is observed in laboratory experiments) and a temperature anomaly recorded at a depth of 30 cm.

  5. Coal seam clue to Abbeystead disaster

    Energy Technology Data Exchange (ETDEWEB)

    1985-04-01

    The Health and Safety Executive Report on the Abbeystead valve house explosion is critically studied. The body of evidence is examined which suggests that the tunnel could have crossed the line of a coal seam. Coal outcrops, bell pit making suggest that a coal seam following the 99 m contour crosses the tunnel near the Rowton Portal, and hence provided a source of methane. Also the formation of stalactites in the tunnel is discussed. Whether or not these mainly mineral formations can grow under water is a matter of debate. If they cannot then significant voids must have been present.

  6. Nature of electromagnetic radiation of a coal seam

    Energy Technology Data Exchange (ETDEWEB)

    Frid, V.I.; Shabarov, A.N.; Proskuryakov, V.M.; Baranov, V.A. (Rossiiskaya Akademiya Nauk (Russian Federation))

    1992-03-01

    Analyzes feasibility of forecasting rock burst hazards on the basis of electromagnetic radiation of a coal seam. Electromagnetic radiation emitted by coal seams situated at depths from 300 to 750 m in a number of coal mines in the Kuzbass was investigated. The investigations were carried out both in coal seams prone to rock bursts and in those without rock burst hazards. Effects of the following factors on the level of electromagnetic radiation were analyzed: moisture content in coal seams, coal mechanical properties, porosity, state of stress, microcracking of coal seams caused by stress concentration, gas desorption from coal. Analyses show that electromagnetic emission supplied reliable information on rock burst hazards. Use of a frequency of about 100 Hz for measuring electromagnetic radiation is recommended. Rock burst forecasting based on measuring electromagnetic radiation of a coal seam was compared to methods based on measuring the rate of cuttings leaving test boreholes and the velocity of gas emitted from the boreholes. 11 refs.

  7. Research on New Method of Full-Seam Mining for Gently Inclined Thick Coal Seams

    Institute of Scientific and Technical Information of China (English)

    赵景礼; 郭志飙; 柳慧鹏; 赵立军

    2002-01-01

    The recovery ratio of top-coal caving mining plays a key role in the development of this mining method. For the proposes to raise the recovery ratio and considering heading advance and roadway maintenance, a new method of full - seam mining for gently inclined thick coal seams is put forward on the basis of a theoretic research and engineering practice.

  8. Draft Genome Sequence of Clostridium sp. Maddingley, Isolated from Coal-Seam Gas Formation Water.

    Science.gov (United States)

    Rosewarne, Carly P; Greenfield, Paul; Li, Dongmei; Tran-Dinh, Nai; Bradbury, Mark I; Midgley, David J; Hendry, Philip

    2013-01-01

    Clostridium sp. Maddingley was isolated as an axenic culture from a brown coal-seam formation water sample collected from Victoria, Australia. It lacks the solventogenesis genes found in closely related clostridial strains. Metabolic reconstructions suggest that volatile fatty acids are the main fermentation end products.

  9. Modelling of Rayleigh-type seam waves in disturbed coal seams and around a coal mine roadway

    Science.gov (United States)

    Essen, Katja; Bohlen, Thomas; Friederich, Wolfgang; Meier, Thomas

    2007-08-01

    Wave propagation in coal seams is numerically modelled in order to identify approaches towards the reconnaissance beyond the heading face of an advancing coal mine roadway. Complete synthetic wavefields including P-SV body waves and Rayleigh-type seam waves are calculated using a Green's function approach for simple, laterally homogeneous models and a parallel elastic 2-D/3-D finite difference modelling code for more realistic geometries. For a simple three-layer model the wavefield within the seam is dominated by a fundamental Rayleigh seam mode symmetrical with respect to the centre of the seam on the vertical component and antisymmetrical on the horizontal component. If the seam contains an interleaved dirt band with higher velocities and density, higher modes dominate the wave propagation, depending on the thickness of the dirt band. Wave propagation in laterally inhomogeneous coal seam models with disturbances like seam ends, faults, thinning, washouts and seam splitting is strongly influenced by the type of disturbance. Amplitudes of seam waves reflected from these disturbances strongly depend on the fault throw and the degree of thinning or washout. In some cases, conversion to higher modes can occur. In all investigated models, those Rayleigh seam wave phases are preferably reflected, which have frequencies above the fundamental mode Airy phase. Lower frequency phases are preferably transmitted. However, seam waves are not reflected from a seam splitting disturbance. Thus a detection of seam splitting with reflected seam waves appears to be impossible. FD computations for 3-D models containing an ending tunnel parallel to the seam and a source beyond the heading face of the tunnel show that seam waves are converted into Rayleigh waves at the tunnel face. They propagate along the surface of the tunnel and interfere with the seam waves propagating beside the tunnel. This effect has to be taken into account for subsequent treatment of experimental data, where

  10. Technology and means of a coal seam interval hydraulic fracturing for the seam degassing intensification

    Science.gov (United States)

    Klishin, VI; Opruk, GY; Tatsienko, AL

    2017-02-01

    Interval hydraulic fracturing use for the seam degassing intensification actuality is explained. The known methods of degassing are reviewed. Technological scheme of the interval coal seam hydraulic fracturing implementation is worked out. The equipment to fulfill degassing intensification measures is suggested.

  11. Stability of Roadway in Upper Seam of Deep Multiple Rich Gas Coal Seams through Ascending Stress-relief Mining

    OpenAIRE

    2015-01-01

    The first mining of a protective coal seam through ascending stress-relief mining is one of the most effective techniques for eliminating the risk of coal and gas outburst during the exploitation of multiple coal seams containing high rich gas. However, the difficulty of controlling roadway stability in the upper protected coal seam above the goaf increases greatly after ascending mining. Based on the geological conditions in Guqiao Coal Mine in China, a numerical simulation model is establis...

  12. Prediction of Coal Seam Methane Enriched Areas Using Seismic Data

    Institute of Scientific and Technical Information of China (English)

    CHEN Tong-jun; CUI Ruo-fei; LIU En-ru; LANG Yu-quan

    2006-01-01

    All coal mine disasters are dynamic geological phenomenon and affected by many factors. However, locating the enriched areas of CSM (coal seam methane) may be the precondition for the successful prediction of such disasters. Traditional methods of investigating CSM enriched areas use limited data and only consider a few important factors. Their success rate is low and cannot meet practical needs. In this paper, an alternative method is proposed. The procedure is given as follows: 1) fracture attributes derived from azimuth variations of P-wave data in coal seams and wall rocks can be extracted; 2) AVO attributes, such as the intercept P and gradient G parameters can be extracted from different azimuths from 3D seismic data; 3) seismic cubes can be inverted and the relative attributes of impedance cubes can be extracted; 4) using a GIS platform, multi-source information can be obtained and analyzed; these include fracture attributes of coal seams and wall rocks, the thickness of coal seams, the distribution of faults and structures, the depth of coal seams, the inclination and exposure of coal seams and the coal rank. Through this processing procedure, methane enriched areas can be systematically detected.

  13. The geomechanics of gas recovery from coal seams

    Science.gov (United States)

    Klimov, D. M.; Karev, V. I.; Kovalenko, Yu. F.

    2015-05-01

    A new approach for the creation of scientific foundations for effective and environmentally safe recovery of methane from coal seams is proposed. A virgin coal seam possesses very low permeability. Free gas is contained in isolated microscopic pores and cracks of the coal seam under a pressure close to the rock pressure. An oriented system of cracks, which forms a coupled system of filtration channels, can be formed by means of directed unloading of the rock pressure from the seam due to expanding gas energy. The parameters of the manufacturing effect on the seam are determined based on physical modeling of actual mechanical and filtration processes using the experimental installation of truly three-axial loading and mathematical modeling.

  14. Applied on bolting-cable anchor support of full-seam roadway in weaker thick coal seam

    Institute of Scientific and Technical Information of China (English)

    赵庆彪; 张生华; 郭励生

    2003-01-01

    The designing method and the supporting mechanism of both bolt and small cable anchor for full-seam roadway in the weaker thick coal seam are systematically analyzed, and the construction technology and the supporting results are briefly summarized.

  15. Greenhouse gas emissions from shallow uncovered coal seams

    Institute of Scientific and Technical Information of China (English)

    Saghafi Abouna

    2014-01-01

    This study discusses a method of quantifying emissions from surface coal mining that has been trialled in Australia. The method is based on direct measurement of surface emissions from uncovered coal seams in mine pits, concurrent measurement of residual gas content of blasted coal in mine pits, and measurement of pre-mining gas content of the same seam from cores retrieved from exploration boreholes drilled away from active mining. The results from one of the mines studied are presented in this paper. In this mine, the pre-mining gas content of the target seam was measured using cores from an exploration borehole away from active mining. Gas content varied from 0.7 to 0.8 m3/t and gas composition varied from 16% to 21% CH4 (84-79% CO2). In-pit measurements included seam surface emissions and residual gas content of blasted and ripped coal. Residual gas content varied from 0.09 to 0.15 m3/t, less than twofold across the mine pit. Composition of the residual gas was in general 90%CO2 and 10%CH4, with slight var-iation between samples. Coal seam surface emissions varied from 1.03 to 7.50 mL of CO2-e per minute and per square meter of the coal seam surface, a sevenfold variation across the mine pit.

  16. Polycyclic aromatic hydrocarbon formation under simulated coal seam pyrolysis conditions

    Institute of Scientific and Technical Information of China (English)

    Liu Shuqin; Wang Yuanyuan; Wang Caihong; Bao Pengcheng; Dang Jinli

    2011-01-01

    Coal seam pyrolysis occurs during coal seam fires and during underground coal gasification.This is an important source of polycyclic aromatic hydrocarbon (PAH) emission in China.Pyrolysis in a coal seam was simulated in a tubular furnace.The 16 US Environmental Protection Agency priority controlled PAHs were analyzed by HPLC.The effects of temperature,heating rate,pyrolysis atmosphere,and coal size were investigated.The results indicate that the 3-ring PAHs AcP and AcPy are the main species in the pyrolysis gas.The 2-ring NaP and the 4-ring Pyr are also of concern.Increasing temperature caused the total PAH yield to go through a minimum.The lowest value was obtained at the temperature of 600 ℃ Higher heating rates promote PAH formation,especially formation of the lower molecular weight PAHs.The typical heating rate in a coal seam,5 ℃/min,results in intermediate yields of PAHs.The total PAHs yield in an atmosphere of N2 is about 1.81 times that seen without added N2,which indicates that an air flow through the coal seam accelerates the formation of PAHs.An increase in coal particle size reduces the total PAHs emission but promotes the formation of 5- and 6-ring PAHs.

  17. Impacts of Coal Seam Gas (Coal Bed Methane) and Coal Mining on Water Resources in Australia

    Science.gov (United States)

    Post, D. A.

    2013-12-01

    Mining of coal bed methane deposits (termed ';coal seam gas' in Australia) is a rapidly growing source of natural gas in Australia. Indeed, expansion of the industry is occurring so quickly that in some cases, legislation is struggling to keep up with this expansion. Perhaps because of this, community concern about the impacts of coal seam gas development is very strong. Responding to these concerns, the Australian Government has recently established an Independent Expert Scientific Committee (IESC) to provide advice to the Commonwealth and state regulators on potential water-related impacts of coal seam gas and large coal mining developments. In order to provide the underlying science to the IESC, a program of ';bioregional assessments' has been implemented. One aim of these bioregional assessments is to improve our understanding of the connectivity between the impacts of coal seam gas extraction and groundwater aquifers, as well as their connection to surface water. A bioregional assessment can be defined as a scientific analysis of the ecology, hydrology, geology and hydrogeology of a bioregion, with explicit assessment of the potential direct, indirect and cumulative impacts of coal seam gas and large coal mining development on water resources. These bioregional assessments are now being carried out across large portions of eastern Australia which are underlain by coal reserves. This presentation will provide an overview of the issues related to the impacts of coal seam gas and coal mining on water resources in Australia. The methodology of undertaking bioregional assessments will be described, and the application of this methodology to six priority bioregions in eastern Australia will be detailed. Preliminary results of the program of research to date will be assessed in light of the requirements of the IESC to provide independent advice to the Commonwealth and State governments. Finally, parallels between the expansion of the industry in Australia with that

  18. Distribution of Heavy Hydrocarbon in Coal Seams and Its Use in Predicting Outburst of Coal

    Institute of Scientific and Technical Information of China (English)

    蒋承林; 李增华; 韩颖

    2003-01-01

    In order to verify whether any special gas component exists in outburst samples or not, coal samples from both outburst coal seams and non-outburst coal seams were collected. Some gases were extracted from the samples and analyzed qualitatively and quantitatively on chromatogram-mass spectrograph. The qualitative analysis show that there is no special gases in coal seams. And the quantitative analysis indicates that the heavy hydrocarbon content in coal samples from outburst coal seams is apparently higher than that from non-outburst district ones, which reflects the damage of geological tectonic movement to coal body in history. Therefore, the heavy hydrocarbon content of coal sample can be used as an index to predict coal outburst.

  19. Theory of gas extraction from coal seams and its use

    Institute of Scientific and Technical Information of China (English)

    FAN Xi-sheng

    2012-01-01

    Gas extraction is one of the main measures of control and use of gas of coal mines.At present,the design method is under the experimental period and do not satisfy the need of practice.In this paper,the theory of gas extraction of coal seams based upon Darcy law was studied.Mathematical model of gas extraction of coal seams was established and two kinds of solving approaches based on computer software and linear approximation were given.The rightness and the validities of the model were examined with a practical example.Results obtained can be used to determine and optimize the parameters related etc.

  20. Coal seam methane distribution and its significance in Pingdingshan mining area

    Institute of Scientific and Technical Information of China (English)

    郭德勇; 周心权; 沈少川; 张晓萍

    2002-01-01

    A study aimed at the coal seam group E and F in Pingdingshan mining area has been completed. This study is on the relationship of the coal-seam methane reserve to coal thickness, coal rank, coal seam depth, surrounding rock and geological structure and other factors. The study indicates that different geological factor plays different role in controlling the law of coal-seam methane reserve. The coal-seam methane rich area, which was formed because of various factors and comprehensive effect, is the coal and methane outburst-prone area, and also the key area for coal-bed methane recovery. Among all factors, coal seam depth and geological structure is more important factor in affecting coal-seam methane content in Pingdingshan mining area.

  1. Gray Comprehensive Evaluation Method on Coal Seam Water Injection in Order of Difficulty

    OpenAIRE

    2016-01-01

    In order to evaluate the coal mine water injection accurately, the gray comprehensive evaluation is applied in this paper, the depth of coal seam, the development degree of coal seam crack, porosity, gas pressure in coal seam, wetting edge of coal, firmness coefficient of coal are chosen as the main index to evaluate the method of water injection into coal mine. The results show that the gray comprehensive evaluation model has a relatively high reliability and accuracy, which can be used to p...

  2. Research on drawing coal effects in the dipping and steep--dipping coal seams

    Institute of Scientific and Technical Information of China (English)

    胡伟; 王窈惠

    2002-01-01

    Controllable drawing roof coal mining method is applied either to rently inclined seam or to big dipping seam. This paper sums up four corresponding methods according to conditions of our country, and analyses the coal-recovering effects and proves applicated conditions and measures for improving by "drawing coal theory of the ellipsoid". Its conclusion basically consists with practice. This work is of guiding meaning for designing drawing coal technology.

  3. The estimation of coal thickness based on Kriging technique and 3D coal seam modeling

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Hu, J.; Zhu, H.; Ding, X. [Tongji University, Shanghai (China)

    2008-07-15

    Based on borehole data, the spatial variation of coal seam thickness was studied. Using contour data, a Triangulated Irregular Network (TIN) model was constructed with a strip algorithm. By using the Kriging method, the thickness at each point of the TIN was calculated. The thickness of coal has the characteristic of uncertainties. The top TIN of the coal seam can be acquired through mapping the bottom TIN with the calculated thickness. A 3D model of the coal seam was constructed by building the corresponding relationship between the top and bottom TIN. 15 refs., 6 figs., 1 tab.

  4. 18 CFR 270.302 - Occluded natural gas produced from coal seams.

    Science.gov (United States)

    2010-04-01

    ... produced from coal seams. 270.302 Section 270.302 Conservation of Power and Water Resources FEDERAL ENERGY... produced from coal seams. A person seeking a determination that natural gas is occluded natural gas produced from coal seams must file an application with the jurisdictional agency which contains...

  5. Palaeoenvironmental reconstruction of Hüsamlar coal seam, SW Turkey

    Indian Academy of Sciences (India)

    Zeynep Büçkün; HüLya İnaner; Riza Görkem Oskay; Kimon Christanis

    2015-06-01

    The Ören and Yatağan Basins in SW Turkey host several Miocene coal deposits currently under exploitation for power generation. The present study aims to provide insight into the palaeoenvironmental conditions, which controlled the formation of the Hüsamlar coal seam located in Ören Basin. The coal seam displays many sharp alternations of matrix lignite beds and inorganic, lacustrine sediment layers. The coal is a medium-to-high ash lignite (10.47–31.16 wt%, on dry basis) with high total sulphur content (up to 10 wt%, on dry, ash-free basis), which makes it prone to self-combustion. The maceral composition indicates that the peat-forming vegetation consisted of both arboreal and herbaceous plants, with the latter being predominant in the upper part of the seam. Mica and feldspars contribute to the low part of the seam; carbonates are dominant in the upper part, whereas quartz and pyrite are present along the entire coal profile. The sudden transitions of the telmatic to the lacustrine regime and reverse is attributed to tectonic movements that controlled water table levels in the palaeomire, which affected surface runoff and hence, clastic deposition.

  6. Study on ascending mining roadway layout of close distance coal seams in deep mine

    Institute of Scientific and Technical Information of China (English)

    SHI Yong-kui; MO Ji

    2007-01-01

    To solve the problems appeared in mining process of No.2 seam, the ascending stress-releasing mining method was adopted. Studying on the reasonable layout of actual mining roadway in upper coal seams is the precondition of successful ascending mining.By using "device of leak measuring by blocking up double ends", it detected the height of overburden water flowing fractured zone originated from sub-coal seams mining. Thus it proved that the actual mining roadway of No.2 upper ascending seam was located in the smooth sagging zone. On the basis of analyzing the stress-releasing effect of sub-coal seams mining to upper coal seams by using RFPA software, it analyzed the stability of up-face coal seams and the reasonable location of starting cut in up-face coal seams. It also analyzed the reasonable gateway location in upper coal seams, which ensured the crossheading in upper coal seams out of the effect of sub-coal work face mining by using theory of underground pressure. Meanwhile, the reasonable pillars dimensions in upper coal seams by building the structure mechanics model of stope were researched. It can make the roadway driven along next goaf to be located in low stress zone, and be beneficial to keeping roads stable owing to less stress of surrounding rock. Finally, it tested the rationality of the layout method of roads in upper coal seams by engineering field measurement in 3221 working face.

  7. Possibilities of working thick brown coal seams in the Stara Jama mine of Zenica mines by sublevel working methods applying self-advancing Westfalia-Luenen powered supports, type B. S. 2. 1 and I. B. S. 2. 2

    Energy Technology Data Exchange (ETDEWEB)

    Bijelic, V.; Ivkovic, M.; Slijepcevic, S.; Krizan, D.

    1980-01-01

    This paper describes the properties of 9 exploitable coal seams of Zenica colliery. Two of them have been intensively exploited over many years. It outlines the development of working methods from room and pillar up to fully mechanized longwall mining. As final result of the efforts made in order to improve the productivity of longwall mining a modified type of Westfalia-Luenen self-advancing powered support is described. The results achieved with this support are shown in a table. (9 refs.) (In Serbo-Croatian).

  8. Influence of Mining Thickness on the Rationality of Upward Mining in Coal Seam Group

    OpenAIRE

    2016-01-01

    This study aimed to determine the influence of mining thickness on the rationality of upward mining in coal seam group. Numerical simulation and theoretical analysis were performed to investigate the influence of the mining thicknesses of initial mining seam on the destruction and pressure relief effect of the upper coal seam in a high-gas coal seam group. The mechanical model of the roof failure based on the mining thickness was established by assuming that the gob formed after a...

  9. PHYSICAL SIMULATION AND ANALYSIS OF METHANE TRANSPORT IN COAL SEAM

    Institute of Scientific and Technical Information of China (English)

    罗新荣; 俞启香

    1994-01-01

    This paper studies the effect of ground stress, pore gas pressure and adsorbed methane on methane transport in coal seam, and researches into the applicability of Darcy's law to methane transport. The additional expansion stress of coal induced by adsorbed methane is measured. The paper establishes the constitutive equation of methane transport, taking ground stress, pore gas pressure and Klinkcnburg's effects into considcration, The features of methane transport under the condition of given stress or strain have been analyzed.

  10. Process for the extraction of thick coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Barsi, K.; Salamon, H.; Solymos, A.; Takacs, J.; Toth, I.

    1983-08-23

    There is disclosed a process for the extraction of thick coal seams by means of which coal seams not extractable in one bank or slice and/or located at peripheral areas may also be extracted under improved mine safety conditions and with high productivity. According to the invention the thick coal seam is if required, divided horizontally and/or vertically into extraction blocks which are bounded and separated by stowing pillars arranged according to the direction of advance of the extraction. The cavity of the pillars is advanced at a level higher than the level of the roof of the extraction space, after which the cavity of the pillar is back-filled. Then the block is extracted by means of block caving in a manner known per se. In a preferred embodiment of the invention incombustible material that agglomerates under the effect of the static pressure of the rock is used for stowing. The utilization of the process for extraction according to the invention results in a considerable increase of intensity. Whether the extraction is in one or more slices and whether using individual self-advancing supports, using track-bound or independent loading/conveyor equipment, an economic extraction of coal seams is achieved.

  11. PLASMA PYROLYSIS OF BROWN COAL

    OpenAIRE

    Plotczyk, W.; Resztak, A.; A.; Szymanski

    1990-01-01

    The specific energy of the substrate is defined as the ratio of the plasma jet energy to the mass of the coal. The influence of the specific energy of the brown coal (10 - 35 MJ/kg) on the yield and selectivity of the gaseous products formation was determined. The pyrolysis was performed in d.c. arc hydrogen plasma jet with the 25 kW power delivered to it. The higher specific energies of coal correlated to the higher conversion degrees of the substrates to C2H2 and CO as well as to the higher...

  12. CO2 Sequestration in Unmineable Coal Seams: Potential Environmental Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Hedges, S.W.; Soong, Yee; McCarthy Jones, J.R.; Harrison, D.K.; Irdi, G.A.; Frommell, E.A.; Dilmore, R.M.; Pique, P.J.; Brown, T.D

    2005-09-01

    An initial investigation into the potential environmental impacts of CO2 sequestration in unmineable coal seams has been conducted, focusing on changes in the produced water during enhanced coalbed methane (ECBM) production using a CO2 injection process (CO2-ECBM). Two coals have been used in this study, the medium volatile bituminous Upper Freeport coal (APCS 1) of the Argonne Premium Coal Samples series, and an as-mined Pittsburgh #8 coal, which is a high volatile bituminous coal. Coal samples were reacted with either synthetic produced water or field collected produced water and gaseous carbon dioxide at 40 οC and 50 bar to evaluate the potential for mobilizing toxic metals during CO2-ECBM/sequestration. Microscopic and x-ray diffraction analysis of the post-reaction coal samples clearly show evidence of chemical reaction, and chemical analysis of the produced water shows substantial changes in composition. These results suggest that changes to the produced water chemistry and the potential for mobilizing toxic trace elements from coalbeds are important factors to be considered when evaluating deep, unmineable coal seams for CO2 sequestration.

  13. Study on the economic mining method for the close quarter coal seams with thin rock sheet

    Institute of Scientific and Technical Information of China (English)

    GOU Pan-feng; CHEN Zhao-qiang; YUN Xiao-you

    2001-01-01

    The paper presents the mining method for the close quarter coal seams with thin rock sheet, that is mining the low coal seam, recovering the top coal seam aft er putting down the roof rock of the low coal seam. Practice has proved that in recovering the top coal outside the face width after the rock between seams fall s naturally or is demolished, the technology is simple, easy to operate and doe s not make a great demand for technical equipment. In the process of recovering t he top coal, the low seam support could not be affected seriously, and two seams mining could be coordinated. Compared with the individual mining method, this m ining method can produce a better economic benefit.

  14. Study on the economic mining method for the close quarter coal seams with thin rock sheet

    Institute of Scientific and Technical Information of China (English)

    勾攀峰; 陈兆强; 员小有

    2001-01-01

    The paper presents the mining method for the close quarter coal seams with thin rock sheet, that is mining the low coal seam, recovering the top coal seam after putting down the roof rock of the low coal seam. Practice has proved that in recovering the top coal outside the face width after the rock between seams falls naturally or is demolished, the technology is simple, easy to operate and does not make a great demand for technical equipment. In the process of recovering the top coal, the low seam support could not be affected seriously, and two seams mining could be coordinated. Compared with the individual mining method, this mining method can produce a better economic benefit.

  15. STUDY ON THE RELATIONSHIP BETWEEN THE DIVERSITY COAL MASS STRUCTURE AND LITHOTYPE OF COAL IN MULTI-COAL SEAM MINE

    Institute of Scientific and Technical Information of China (English)

    吴基文; 赵志根; 陈资平

    1999-01-01

    Through site observation and indoor measurements in XieJiaji No.2 Coal Mine in Huainen and Luling Coal Mine in Huaibei, it is discovered that the fragmentation degree are different in different coal seams in same mining district and even in sublevels of the same coal seam, the coal mass structures exist much difference. By analyzing the relationship between the constitution of coal matters and the epigenesis breakage of coal. This paper points out that the internal factor which causes the diversity of the coal mass structure comes from the diversity in the contents of telocollinite and desmocollinite in the vitrinite. The contenet of desmocollinite is higher than that of telocollinite in intact coal seam (sublevel) but the former is less than the later in breaking sublevel, the diversity of constituent content more affects the epigenetic fragmentation degree of coal seam. The content of desrnocollinite proves lower than that of telocollinite in the broken coal seam. The new understanding has directing, and reference for the study of coal petrology, coal mine gas geology and coal methane.

  16. Guided modes in coal seams and their application to underground seismic surveying

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, P.E.; Mason, I.M.

    1975-01-01

    Underground seismic surveying of coal seams can be performed using the channel waves guided by the low velocity coal layer. The roadway modes, i.e. the modes guided by the free face of the coal seam, are analysed. The knowledge of channel modes and roadway modes are shown to be fundamental to the interpretation of any survey data. Detailed calculations of the channel modes and the pulse propagation in a particular coal seam are presented.

  17. Stochastic reservoir simulation for the modeling of uncertainty in coal seam degasification

    Science.gov (United States)

    Karacan, C. Özgen; Olea, Ricardo A.

    2015-01-01

    Coal seam degasification improves coal mine safety by reducing the gas content of coal seams and also by generating added value as an energy source. Coal seam reservoir simulation is one of the most effective ways to help with these two main objectives. As in all modeling and simulation studies, how the reservoir is defined and whether observed productions can be predicted are important considerations.

  18. Coal and rock fissure evolution and distribution characteristics of multi-seam mining

    Institute of Scientific and Technical Information of China (English)

    Zhang Dongming; Qi Xiaohan; Yin Guangzhi; Zheng Binbin

    2013-01-01

    Henan Pingdingshan No.10 mine is prone to both coal and gas outbursts. The E9-10 coal seam is the main coal-producing seam but has poor quality ventilation, thus making it relatively difficult for gas extraction. The F15 coal seam, at its lower section, is not prone to coal and gas outbursts. The average seam separa-tion distance of 150 m is greater than the upper limit for underside protective seam mining. Based on borehole imaging technology for field exploration of coal and rock fracture characteristics and discrete element numerical simulation, we have studied the evolution laws and distribution characteristics of the coal and rock fissure field between these two coal seams. By analysis of the influential effect of group F coal mining on the E9-10 coal seam, we have shown that a number of small fissures also develop in the area some 150 m above the overlying strata. The width and number of the fissures also increase with the extent of mining activity. Most of the fissures develop at a low angle or even parallel to the strata. The results show that the mining of the F15 coal seam has the effect of improving the permeability of the E9-10 coal seam.

  19. Deep coal seams as a greener energy source: a review

    Science.gov (United States)

    Ranathunga, A. S.; Perera, M. S. A.; Ranjith, P. G.

    2014-12-01

    Today, coal and oil are the main energy sources used in the world. However, these sources will last for only a few decades. Hence, the investigation of possible energy sources to meet this crisis has become a crucial task. Coal bed methane (CBM) is a potential energy source which can be used to fulfil the energy demand. Since the amount of carbon dioxide (CO2) emitted to the atmosphere from the use of CBM is comparatively very low compared to conventional energy sources, it is also a potential mitigation option for global warming. This paper reviews CBM recovery techniques with particular emphasis on CO2-enhanced coal bed methane (CO2-ECBM) recovery. The paper reviews (1) conventional CBM recovery techniques and problems associated with them, (2) CBM production-enhancement methods, including hydro-fracturing and enhanced CBM recovery techniques, such as N2-ECBM and CO2-ECBM, (3) the importance of the CO2-ECBM technique compared to other methods and problems with it, (4) the effect of CO2 injection during the CO2-ECBM process on coal seam permeability and strength and (5) current CO2-ECBM field projects and their progress. Although conventional CBM recovery methods are simple (basically related to the drawdown of the reservoir pressure to release methane from it), they are inefficient for the recovery of a commercially viable amount of methane from coal seams. Therefore, to enhance methane production, several methods are used, such as hydro-fracturing and ECBM (N2-ECBM and CO2-ECBM). The CO2-ECBM process has a number of advantages compared to other methane recovery techniques, as it contributes to the mitigation of the atmospheric CO2 level, is safer and more economical. However, as a result of CO2 injection into the coal seam during the CO2-ECBM process, coal mass permeability and strength may be crucially changed, due to the coal matrix swelling associated with CO2 adsorption into the coal matrix. Both injecting CO2 properties (gas type, CO2 phase and pressure

  20. Gray Comprehensive Evaluation Method on Coal Seam Water Injection in Order of Difficulty

    Directory of Open Access Journals (Sweden)

    Liu Xiao Li

    2016-01-01

    Full Text Available In order to evaluate the coal mine water injection accurately, the gray comprehensive evaluation is applied in this paper, the depth of coal seam, the development degree of coal seam crack, porosity, gas pressure in coal seam, wetting edge of coal, firmness coefficient of coal are chosen as the main index to evaluate the method of water injection into coal mine. The results show that the gray comprehensive evaluation model has a relatively high reliability and accuracy, which can be used to predict the difficulty degree of water injection.

  1. Variation in gas drainage rate from a coal seam during mining

    Institute of Scientific and Technical Information of China (English)

    Li; Gang; Qi; Qingxin; Li; Hongyan; Fan; Xisheng

    2012-01-01

    Gas flow patterns during draining of gas from a coal seam during mining are discussed.The coal seam is treated as a dual medium with both pores and cracks.The seepage,diffusion,and desorption processes are treated using a gas flow equation that describes flow around drill holes.MATLAB is used to solve the differential equations.The permeability tracer test results from a mined coal seam are used to study the variation in gas drainage from a coal seam during mining.The results show that mining can increase the permeability of a coal seam,which then increases the gas drainage.There are inflection points in this variation over time.A close relationship between this variation and the rate of change in coal seam permeability is observed.

  2. Gas drainage technology of high gas and thick coal seam

    Institute of Scientific and Technical Information of China (English)

    HE Tian-cai; LI Hai-gui; ZHANG Hai-jun

    2009-01-01

    Gas drainage in Jincheng Mining Group Co., Ltd. was introduced briefly and the importance of gas drainage in gas control was analyzed. Combined with coal-bed gas oc-currence and gas emission, the double system of gas drainage was optimized and a pro-gressive gas drainage model was experimented on. For guaranteed drainage, excavation and mining and realization of safety production and reasonable exploitation of gas in coal seams, many drainage methods were adopted to solve the gas problem of the working face.

  3. The innovational mining technology of fully mechanized mining on thin coal seam

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, G.; Sun, Q.; Song, H. [China Ocean University, Qingdao (China)

    2007-03-15

    The paper describes the innovational fully mechanized mining technology practised on thin coal seams in Tianchen coal mine. This mining technology combined fully mechanized mining and orthodox working face mining. The technology is suitable for mining of particularly thin coal seams. 7 refs., 1 fig., 1 tab.

  4. Evaluation of coal bed methane potential of coal seams of Sawang Colliery, Jharkhand, India

    Indian Academy of Sciences (India)

    Anil M Pophare; Vinod A Mendhe; A Varade

    2008-04-01

    The coal seams of Sawang Colliery, East Bokaro Coalfields are bituminous to sub-bituminous in nature and categorized as high gaseous seams (degree II to degree III level). These seams have the potential for coal bed methane (CBM) and their maturity increases with increasing depth, as a result of enhanced pressure-temperature conditions in the underground. The vitrinite maceral group composition of the investigated coal seams ranges from 62.50-83.15%, whereas the inertinite content varies from 14.93-36.81%. The liptinite content varies from 0.66% to 3.09%. The maximum micro-pores are confined within the vitrinite group of macerals. The coal seams exhibit vitrinite reflectance values (Ro% calculated) from 0.94% (sample CG-97) to 1.21% (sample CG-119). Proximate analyses of the investigated coal samples reveal that the moisture content (M%) ranges from 1.28% to 2.98%, whereas, volatile matter (VM%) content is placed in the range of 27.01% to 33.86%. The ash content (A%) ranges from 10.92% to 30.01%. Fixed carbon (FC%) content varies from 41.53% to 55.93%. Fuel ratio variation shows a restricted range from 1.53 to 1.97. All the coal samples were found to be strongly caking and forming coke buttons. The present study is based on the adsorption isotherm experiments carried out under controlled P-T conditions for determination of actual gas adsorption capacity of the coal seams. This analysis shows that the maximum methane gas adsorbed in the coal sample CG-81 is 17m3/t (Std. daf), at maximum pressure of 5.92MPa and experimental temperature of 30°C. The calculated Langmuir regression parameters PL and VL range from 2.49 to 3.75MPa and 22.94 to 26.88m3/t (Std. daf), respectively.

  5. The migration law of overlay rock and coal in deeply inclined coal seam with fully mechanized top coal caving.

    Science.gov (United States)

    Liu, Jian; Chen, Shan-Le; Wang, Hua-Jun; Li, Yu-Cheng; Geng, Xiaowei

    2015-07-01

    In a mine area, some environment geotechnics problems always occure, induced by mined-out region such as the subsidence and cracks at ground level, deformation and destruction of buildings, landslides destruction of water resources and the ecological environment. In order to research the migration of surrounding rock and coal in steeply inclined super high seams which used fully mechanized top coal caving, a working face of a certain mine was made as an example, analyzed the migration law of the overlay rock and coal under different caving ratio of fully mechanized top coal caving with numerical simulation analysis. The results suggest that the laws of overlay rock deformation caused by deeply inclined coal seam were different from horizontal coal seam. On the inclined direction, with an increase of dip angle and caving ratio, the vertical displacement of overlay rock and coal became greater, the asymmetric phenomenon of vertical displacement became obvious. On the trend direction, active region and transition region in goaf became smaller along with the increase of mining and caving ratio. On the contrary, the stable region area became greater. Therefore, there was an essential difference between the mechanism of surface movement deformation with deeply inclined coal seam and that with horizontal coal seam.

  6. Nitrogen Injection To Flush Coal Seam Gas Out Of Coal: An Experimental Study

    Science.gov (United States)

    Zhang, Lei; Aziz, Naj; Ren, Ting; Nemcik, Jan; Tu, Shihao

    2015-12-01

    Several mines operating in the Bulli seam of the Sydney Basin in NSW, Australia are experiencing difficulties in reducing gas content within the available drainage lead time in various sections of the coal deposit. Increased density of drainage boreholes has proven to be ineffective, particularly in sections of the coal seam rich in CO2. Plus with the increasing worldwide concern on green house gas reduction and clean energy utilisation, significant attention is paid to develop a more practical and economical method of enhancing the gas recovery from coal seams. A technology based on N2 injection was proposed to flush the Coal Seam Gas (CSG) out of coal and enhance the gas drainage process. In this study, laboratory tests on CO2 and CH4 gas recovery from coal by N2 injection are described and results show that N2 flushing has a significant impact on the CO2 and CH4 desorption and removal from coal. During the flushing stage, it was found that N2 flushing plays a more effective role in reducing adsorbed CH4 than CO2. Comparatively, during the desorption stage, the study shows gas desorption after N2 flushing plays a more effective role in reducing adsorbed CO2 than CH4.

  7. Characteristics of the Thorez open pit brown coal mine in Hungary

    Energy Technology Data Exchange (ETDEWEB)

    Benedek, M.

    1984-01-01

    The Hungarian (VNR) brown coal deposits have a large number of thin and varying quality seams. The problem of selecting optimal equipment and technology for mining is determined by finding the parameters of a rotary complex and then the parameters of the technology.

  8. Application of Seismic Anisotropy Caused by Fissures in Coal Seams to the Detection of Coal-bed Methane Reservoirs

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Coal-bed methane is accumulated in micro-fissures and cracks in coal seams. The coal seam is the source terrace and reservoir bed of the coal-bed methane (Qian et al., 1996). Anisotropy of coal seams is caused by the existence of fissures. Based on the theory of S wave splitting: an S wave will be divided into two S waves with nearly orthogonal polarization directions when passing through anisotropic media, i.e. the fast S wave with its direction of propagation parallel to that of the fissure and slow S wave with the direction of propagation perpendicular to that of the fissure.This paper gives the results of laboratory research and field test on the S wave splitting caused by coal-seam fissures. The results show that it is feasible to detect fissures in coal seams by applying the converted S wave and finally gives the development zone and development direction of these fissures.

  9. Influence of Mining Thickness on the Rationality of Upward Mining in Coal Seam Group

    Directory of Open Access Journals (Sweden)

    Y. Li

    2016-04-01

    Full Text Available This study aimed to determine the influence of mining thickness on the rationality of upward mining in coal seam group. Numerical simulation and theoretical analysis were performed to investigate the influence of the mining thicknesses of initial mining seam on the destruction and pressure relief effect of the upper coal seam in a high-gas coal seam group. The mechanical model of the roof failure based on the mining thickness was established by assuming that the gob formed after adjacent panels have fully been caved is the infinite plane. On the basis of this model, an equation was derived to calculate the roof failure height of the panel. Considering the geological conditions of No. 9 and No. 12 coal seams of Zhaogezhuang Coal Mine, economic effectiveness, and proposed techniques, we concluded that the top layer (4 m of the No. 12 coal seam should be mined first. The top layer of the No. 9 coal seam should be subsequently mined. The topcaving technique was applied to the exploitation of the lower layer of the No. 12 coal seam. Practically monitored data revealed that the deformation and failure of the No. 2699 panel roadway was small and controllable, the amount of gas emission was reduced significantly, and the effect of upward mining was active. The results of this study provide theory basics for mine designing, and it is the provision of a reference for safe and efficient coal exploitation under similar conditions.

  10. Stress-strain distribution at the boundary area of coal seams containing nonuniformities

    Energy Technology Data Exchange (ETDEWEB)

    Khaimova-Mal' kova, R.I.

    1986-01-01

    Discusses results of investigations carried out with the help of the finite element method in a 2 m thick coal seam at 400 m level, having varying properties and nonuniformities. Shows that considerable areas with horizontal deformation appear in soft coal which may result in vertical fissuring parallel to headings. States that presence of soft and hard inclusions in coal seams affect stress-strain state and stability of boundary areas and lead to spasmodic changes in stress-strain intensity which result in dynamic phenomena particularly in coal seams which are prone to sudden gas and coal outbursts. 3 refs.

  11. Pressure relief, gas drainage and deformation effects on an overlying coal seam induced by drilling an extra-thin protective coal seam

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-bo; CHENG Yuan-ping; SONG Jian-cheng; SHANG Zheng-jie; WANG Liang

    2009-01-01

    Numerical simulations and field tests were used to investigate the changes in ground stress and deformation of, and gas flow from, a protected coal seam under which an extra-thin coal seam was drilled. The geological conditions were: 0.5 meter min-ing height, 18.5 meter coal seam spacing and a hard limestone/fine sandstone inter-stratum. For these conditions we conclude: 1) the overlying coal-rock mass bends and sinks without the appearance of a caving zone, and 2) the protected coal seam is in the bending zone and undergoes expansion deformation in the stress-relaxed area. The deformation was 12 mm and the relative defor-mation was 0.15%. As mining proceeds, deformation in the protected layer begins as compression, then becomes a rapid expansion and, finally, reaches a stable value. A large number of bed separation crannies are created in the stress-relaxed area and the perme-ability coefficient of the coal seam was increased 403 fold. Grid penetration boreholes were evenly drilled toward the protected coal seam to affect pressure relief and gas drainage. This made the gas pressure decrease from 0.75 to 0.15 Mpa, the gas content de-crease from 13 to 4.66 m3/t and the gas drainage reach 64%.

  12. Stimulation of commercial coal seam methane production aimed at improving mining technology

    OpenAIRE

    2016-01-01

    The relevance of the current research is due to the urgent need to revise the existing normative bases and procedures involved in intensive development of coal-methane deposits and commercial production of coal seam methane. The article presents the analysis of data on coal production volume and amount of methane emitted into the atmosphere in Kuzbass. There is a need to develop the exploration techniques that would allow implementing pre-mining gas drainage of coal seams and provide the comp...

  13. Thermal effects of magmatic sills on coal seam metamorphism and gas occurrence

    Science.gov (United States)

    Wang, Liang; Cheng, Long-biao; Cheng, Yuan-ping; Yin, Guang-zhi; Cai, Chun-cheng; Xu, Chao; Jin, Kan

    2014-04-01

    Igneous intrusions in coal seams are found in 80 % of coal mines in the Huaibei coalfield, China, and coal and gas outburst accidents have occurred 11 times under a 120-m-thick sill in the Haizi mining field. The magma's heat had a significant controlling effect on coal seam gas occurrence. Based on theoretical analysis, experimental tests and site validation, we analyzed the temperature distribution following magma intrusion into coal measure strata and the variations in multiple physical parameters and adsorption/desorption characteristics between the underlying coal seams beneath the sill in the Haizi mining field and coal seams uninfluenced by magma intrusion in the adjacent Linhuan mining field. The research results show that the main factors controlling the temperature distribution of the magma and surrounding rocks in the cooling process include the cooling time and the thickness and initial temperature of the magmatic rock. As the distance from sill increases, the critical effective temperature and the duration of sustained high temperatures decrease. The sill in the Haizi mining field significantly promoted coal seam secondary hydrocarbon generation in the thermally affected area, which generated approximately 340 m3/t of hydrocarbon. In the magma-affected area, the metamorphic grade, micropore volume, amount of gas adsorption, initial speed of gas desorption, and amount of desorption all increase. Fluid entrapment by sills usually causes the gas pressure and gas content of the underlying coal seams to increase. As a result, the outburst risks from coal seams increases as well.

  14. Permeability Prediction in Deep Coal Seam: A Case Study on the No. 3 Coal Seam of the Southern Qinshui Basin in China

    OpenAIRE

    2013-01-01

    The coal permeability is an important parameter in mine methane control and coal bed methane (CBM) exploitation, which determines the practicability of methane extraction. Permeability prediction in deep coal seam plays a significant role in evaluating the practicability of CBM exploitation. The coal permeability depends on the coal fractures controlled by strata stress, gas pressure, and strata temperature which change with depth. The effect of the strata stress, gas pressure, and strata tem...

  15. Microcosmic analysis of ductile shearing zones of coal seams of brittle deformation domain in superficial lithosphere

    Institute of Scientific and Technical Information of China (English)

    JU; Yiwen; WANG; Guiliang; JIANG; Bo; HOU; Quanlin

    2004-01-01

    The ductile shearing zones of coal seams in a brittle deformation domain in superficial lithosphere are put forward based on the study on bedding shearing and ductile rheology of coal seams. The macrocosmic and microcosmic characteristics include wrinkle fold, mymonitized zones and ductile planar structure of coal seams, etc., while the microcosmic characteristics may also include different optic-axis fabrics and the anisotropy of vitrinite reflectance as well as the change of chemical structure and organic geochemistry components. The forming mechanism is analyzed and the strain environment of ductile shearing zones of coal seams discussed. The result indicates that, in the superficial brittle deformation domain, the coal seams are easy to be deformed, resulting in not only brittle deformation but also ductile shearing deformation under the action of force. Because of simple shearing stress, the interlayer gliding or ductile rheology may take place between coal seams and wall rocks. Therefore, many ductile shearing zones come into being in superficial lithosphere (<5 km). The research on ductile shearing zone of brittle deformation domain in superficial lithosphere is significant not only theoretically for the study of ductile shearing and ductile rheology of the lithosphere but also practically for the structural movement of coal seams, the formation and accumulation of coal-bed methane, and the prevention and harness of gas burst in coal mine.

  16. Impacts of Coal Seam Gas (Coal Bed Methane) Extraction on Water Resources in Australia

    Science.gov (United States)

    Post, David

    2016-04-01

    While extraction of methane from shale gas deposits has been the principal source of the recent expansion of the industry in the United States and Europe, in Australia extraction of methane from coal bed methane deposits (termed 'coal seam gas' in Australia) has been the focus to date. The two sources of methane share many of the same characteristics including the potential requirement for hydraulic fracturing. However, as coal seam gas deposits generally occur at shallower depths than shale gas, the potential impacts of extraction on surface and groundwater resources may be of even greater concern. In Australia, an Independent Expert Scientific Committee (IESC) has been established to provide scientific advice to federal and state government regulators on the impact that coal seam gas and large coal mining developments may have on water resources. This advice is provided to enable decisions to be informed by the best available science about the potential water-related impacts associated with these developments. To support this advice, the Australian Government Department of the Environment has implemented a programme of research termed 'bioregional assessments' to investigate these potential impacts. A bioregional assessment is defined as a scientific analysis of the ecology, hydrology, geology and hydrogeology of a bioregion with explicit assessment of the potential direct, indirect and cumulative impacts of coal seam gas and large coal mining development on water resources. These bioregional assessments are currently being carried out across large portions of eastern Australia underlain by coal reserves. Further details of the programme and results to date can be found at http://www.bioregionalassessments.gov.au. Surface water and groundwater modelling is now complete for two regions where coal seam gas development may proceed, namely the Clarence-Moreton and Gloucester regions in eastern New South Wales. This presentation will discuss how the results of these

  17. Calculation of gas content in coal seam influenced by in-situ stress grads and ground temperature

    Institute of Scientific and Technical Information of China (English)

    王宏图; 李时雨; 吴再生; 杨晓峰; 秦大亮; 杜云贵

    2002-01-01

    On the basis of the analysis of coal-bed gas pressure in deep mine, and the coal-bed permeability (k) and the characteristic of adsorption parameter (b) changing with temperature, the author puts forward a new calculating method of gas content in coal seam influenced by in-situ stress grads and ground temperature. At the same time, the contrast of the measuring results of coal-bed gas pressure with the computing results of coal-bed gas pressure and gas content in coal seam in theory indicate that the computing method can well reflect the authenticity of gas content in coal seam,and will further perfect the computing method of gas content in coal seam in theory,and have important value in theory on analyzing gas content in coal seam and forecasting distribution law of gas content in coal seam in deep mine.

  18. Geological evaluation on productibility of coal seam gas; Coal seam gas no chishitsugakuteki shigen hyoka ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, K. [University of Shizuoka, Shizuoka (Japan). Faculty of Education

    1996-09-01

    Coal seam gas is also called coal bed methane gas, indicating the gas existing in coal beds. The gas is distinguished from the oil field based gas, and also called non-conventional type gas. Its confirmed reserve is estimated to be 24 trillion m {sup 3}, with the trend of its development seen worldwide as utilization of unused resource. For the necessity of cultivating relevant technologies in Japan, this paper considers processes of production, movement, stockpiling, and accumulation of the gas. Its productibility is controlled by thickness of a coal bed, degree of coalification, gas content, permeability, groundwater flow, and deposition structure. Gas generation potential is evaluated by existing conditions of coal and degree of coalification, and methane production by biological origin and thermal origin. Economically viable methane gas is mainly of the latter origin. Evaluating gas reserve potential requires identification of the whole mechanism of adsorption, accumulation and movement of methane gas. The gas is expected of effect on environmental aspects in addition to availability as utilization of unused energy. 5 figs.

  19. Discussion of the indexes of nonoutburst coal seam upgrade and its corresponding critical values

    Institute of Scientific and Technical Information of China (English)

    WEI dian-ping; LIU Yan-wei; LIU Ming-ju; MENG Lei

    2009-01-01

    In view of the measurement difficulties of indexes recommended by the 50 Items Experience of Coal Mine Gas Prevention in the process of the nonoutburst coal seam upgrade, this paper took the No.8 coal seam of Huainan Mining Group as research object. Discussed the suitability of indexes and corresponding critical values, put forward method in determining the indexes and its critical values by analysis and investigation of the gas geological condition and the-spot tracking near position where an outburst occurred combined with laboratory experiment, and established the indexes and its critical values of nonoutburst coal seam upgrade in No.8 coal seam of Huainan Mining Group. The results show that it is suitable to take gas content and tectonic soft coal thickness easily to gain in routine production as primary upgrade indexes that its critical values are 7.5 m3/t and 0.8 m, respectively. In addition, takefvalue and Ap value as auxiliary indexes.

  20. Mathematical modeling for coupled solid elastic-deformation and gas leak flow in multi-coal-seams

    Institute of Scientific and Technical Information of China (English)

    孙培德

    2002-01-01

    Based on the new viewpoint of solid and gas interaction mechanics, gas leakage in a double deformable coal seam can be understood. That is, under the action of geophysical fields, the methane flow in a double deformable coal seam can be essentially considered to be compressible with time-dependent and mixed permeation and diffusion through a pore-cleat deformable heterogeneous and anisotropy medium. Based on this new viewpoint, a coupled mathematical model for coal seam deformation and gas leakage in a double coal seam was formulated and numerical simulations for gas emission from the coal seam are presented. It is found that coupled models might be closer to reality.

  1. Some approaches to handling hydrogen sulphide in coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Gillies, A.D.S.; Kizil, M.S.; Wu, H.W.; Harvey, T. [University of Queensland, Qld. (Australia). Department of Mining, Minerals and Materials Engineering

    2001-07-01

    The study addresses Hydrogen Sulphide (H{sub 2}S) in coal seams. The objectives of the project were to undertake a comprehensive series of interrelated studies to gain a full understanding of this complex mine production problem. The goal was to understand how, where and why high concentration zones of H{sub 2}S occur, how does gas release from the coal mass occur, can concentrations be diluted or neutralised through improved ventilation, water, chemical or microbiological infusion, chemical solution sprays and can mining approaches be modified to contain the problem. A multidisciplined approach has been used for related investigations. Systems and the output streams available for H{sub 2}S detection and monitoring have been examined. The large variations in H{sub 2}S concentration measurements from different face sources and the physical differences in the longwall face, ventilation plan, and operating procedures make the interpretation of gas concentration data difficult. Respiratory filters represent a cost-effective and short-term safe way to protect miners from potentially lethal environment. A selection of cartridge and Racal airstream helmet filters has been described and some tests into filter life and efficiency undertaken. The mine ventilation system can be modified to allow safe production through H{sub 2}S affected zones. Designs for maximising safe production through affected mine panel or development headings have been tested. Mining options to reduce H{sub 2}S emissions have also been examined. A major program of in-seam chemical neutralisation infusion trials was undertaken. The basic aim of the chemical infusion process is to prestrip a significant proportion of H{sub 2}S to allow coal mining to proceed in a safe working environment at an economic production rate. Some approaches to analysis of results and evaluating the efficiency of the approach have been given. 12 refs., 8 figs.

  2. Coal slurry - a problem of the brown coal industry

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, H.; Hielscher, R.; Mohry, J.

    1983-01-01

    Technological and economic aspects are examined for processing coal-containing waste water from brown coal preparation plants in the German Democratic Republic. In 1979, 106.8 Mm/sup 3/ of coal slurry were produced by the GDR brown coal industry, with a coal fine content ranging between 7.8 g/l and 20.4 g/l. This amounts to 2.6 Mt/y of coal which is 1% of the annual brown coal production. Technological variants of processing and utilizing coal slurry are discussed. At a number of major coal preparation plants, coal slurry is flushed into sedimentation lakes. After a 2 to 3 year drying period, a 6 to 10 m thick layer of coal is recovered. Technologies of coal slurry processing with the aim of recovering coal fines are enumerated. Equipment for these processes include, filters, centrifuges, dryers, etc. Recovered coal can be used as fuel or processed into fertilizer in combination with fly ash and other waste products. 12 references.

  3. Gas seepage equation of deep mined coal seams and its application

    Institute of Scientific and Technical Information of China (English)

    HU Guo-zhong; WANG Hong-tu; TAN Hai-xiang; FAN Xiao-gang; YUAN Zhi-gang

    2008-01-01

    In order to obtain a gas seepage law of deep mined coal seams, according to the properties of eoalbed methane seepage in in-situ stress and geothermal temperature fields, the gas seepage equation of deep mined coal seams with the Klinkenberg effect was obtained by confirming the coalbed methane permeability in in-situ stress and geothermal temperature fields. Aimed at the condition in which the coal seams have or do not have an outcrop and outlet on the ground, the application of the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields on the gas pressure calculation of deep mined coal seams was investigated. The comparison between calculated and measured results indicates that the calculation method of gas pressure, based on the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields can accurately be identical with the measured values and theoretically perfect the calculation method of gas pressure of deep mined coal seams.

  4. Combined ANN prediction model for failure depth of coal seam floors

    Institute of Scientific and Technical Information of China (English)

    WANG Lian-guo; ZHANG Zhi-kang; LU Yin-long; YANG Hong-bo; YANG Sheng-qiang; SUN Jian; ZHANG Jin-yao

    2009-01-01

    Failure depth of coal seam floors is one of the important considerations that must be kept in mind when mining is carried out above a confined aquifer. In order to study the factors that affect the failure depth of coal seam floors such as mining depth, coal seam pitch, mining thickness, workface length and faults, we propose a combined artificial neural networks (ANN) prediction model for failure depth of coal seam floors on the basis of existing engineering data by using genetic algorithms to train the ANN. A practical engineering application at the Taoyuan Coal Mine indicates that this method can effectively determine the network struc-ture and training parameters, with the predicted results agreeing with practical measurements. Therefore, this method can be applied to relevant engineering projects with satisfactory results.

  5. Behaviors of overlying strata in extra-thick coal seams using top-coal caving method

    Directory of Open Access Journals (Sweden)

    Bin Yu

    2016-04-01

    Full Text Available Accidents such as support failure and excessive deformation of roadways due to drastic changes in strata behaviors are frequently reported when mining the extra-thick coal seams Nos. 3–5 in Datong coal mine with top-coal caving method, which significantly hampers the mine's normal production. To understand the mechanism of strata failure, this paper presented a structure evolution model with respect to strata behaviors. Then the behaviors of strata overlying the extra-thick coal seams were studied with the combined method of theoretical analysis, physical simulation, and field measurement. The results show that the key strata, which are usually thick-hard strata, play an important role in overlying movement and may influence the mining-induced strata behaviors in the working face using top-coal caving method. The structural model of far-field key strata presents a “masonry beam” type structure when “horizontal O-X” breakage type happens. The rotational motion of the block imposed radial compressive stress on the surrounding rock mass of the roadway. This can induce excessive deformation of roadway near the goaf. Besides, this paper proposed a pre-control technology for the hard roof based on fracture holes and underground roof pre-splitting. It could effectively reduce stress concentration and release the accumulated energy of the strata, when mining underground coal resources with top-coal caving method.

  6. Floral assemblage of the `D` coal seam (Cretaceous): implications for banding characteristics in New Zealand coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Ward, S.D.; Moore, T.A.; Newman, J. [University of Canterbury, Christchurch (New Zealand). Dept. of Geology

    1995-09-01

    Two complete vertical sections were studied from the uppermost Cretaceous `D` coal seam near Greymouth, New Zealand. The thickest and most concentrated vitrain bands occur in the paleomire centre and bands are thinner and less abundant at the paleomire margin. Botanical analysis of the vitrain bands indicates they formed entirely from the secondary xylem (wood) of gymnosperms. Palynomorphs indicate that there is no consistent correlation between conifer pollen abundance and the degree of vitrain banding. However, maximum preservation of vitrain bands coincides with an inferred transition from a rheotrophic mire (as indicated by Phyllocladidites mawsonii pollen) to an acidic and possibly ombrotrophic system (as indicated by the abundance of Gleicheniaceae spores). This suggests that the presence/absence of gymnosperm secondary xylem as vitrain bands is controlled at least in part by mire chemistry.

  7. Working of spontaneously combustible coal seams with automatic air pressure regulation in the excavation field

    Energy Technology Data Exchange (ETDEWEB)

    Golik, A.S.; Churikov, Yu.V.; Troyan, N.P.

    1980-01-01

    A demonstration is made of the effectiveness of using an automatic air pressure control system during the working of spontaneously combustible coal seams in order to control endogenic fires and gas. 2 figures.

  8. Stimulation of commercial coal seam methane production aimed at improving mining technology

    Science.gov (United States)

    Shubina, E. A.; Lukyanov, V. G.

    2016-09-01

    The relevance of the current research is due to the urgent need to revise the existing normative bases and procedures involved in intensive development of coal-methane deposits and commercial production of coal seam methane. The article presents the analysis of data on coal production volume and amount of methane emitted into the atmosphere in Kuzbass. There is a need to develop the exploration techniques that would allow implementing pre-mining gas drainage of coal seams and provide the companies with the guidance on coal seam methane drainage in very gassy coal mines. Commercial production of methane should become an integral part of economy and energy balance of the Russian Federation, which, in its turn, would enhance environmental protection due to reducing methane emissions, the largest source of greenhouse effect.

  9. Forecasting Fractures in Coal Seams by Using Azimuthal Anisotropy from P-Wave Seismic Data

    Institute of Scientific and Technical Information of China (English)

    DONG Shou-hua; YUE Jian-hua; ZHANG Fen-xuan

    2007-01-01

    If the thickness of coal seams and the lithology of both roofs and floors of coal seams have not changed at all or only a little, then it is thought that the elastic anisotropy of coal seams depends mainly on fractures and obeys the horizontally symmetric model of an azimuth anisotropy. For a fixed offset, the amplitude A of the reflection P-wave and the cosine of 2 (ψ) has an approximately linear relation, ( (ψ) is the source-detector azimuth with respect to the fracture strike. Based on this relationship, many things can be done, such as the extraction of macro bins, the correction of residual normal moveout, the formation of azimuth gather, the transformation and normalization of azimuth gathers and the extraction of reflection wave amplitudes of coal seams. The least squares method was used to inverse theoretically the direction and density of fractures of coal seams. The result is in good agreement with the regional geological structure, indicating that the azimuth anisotropic analysis of the P-wave is feasible in evaluating the density and direction of fractures in coal seams.

  10. Phenomenon of methane driven caused by hydraulic fracturing in methane-bearing coal seams

    Institute of Scientific and Technical Information of China (English)

    Huang Bingxiang; Cheng Qingying; Chen Shuliang

    2016-01-01

    The methane concentration of the return current will always be enhanced to a certain degree when hydraulic fracturing with bedding drilling is implemented to a gassy coal seam in an underground coal mine. The methane in coal seam is driven out by hydraulic fracturing. Thus, the phenomenon is named as methane driven effect of hydraulic fracturing. After deep-hole hydraulic fracturing at the tunneling face of the gassy coal seam, the coal methane content exhibits a‘low-high-low”distribution along exca-vation direction in the following advancing process, verifying the existence of methane driven caused by hydraulic fracturing in methane-bearing coal seam. Hydraulic fracturing causes the change of pore-water and methane pressure in surrounding coal. The uneven distribution of the pore pressure forms a pore pressure gradient. The free methane migrates from the position of high pore (methane) pressure to the position of low pore (methane) pressure. The methane pressure gradient is the fundamental driving force for methane-driven coal seam hydraulic fracturing. The uneven hydraulic crack propagation and the effect of time (as some processes need time to complete and are not completed instantaneously) will result in uneven methane driven. Therefore, an even hydraulic fracturing technique should be used to avoid the negative effects of methane driven; on the other hand, by taking fully advantage of methane driven, two technologies are presented.

  11. New development of longwall mining equipment based on automation and intelligent technology for thin seam coal

    Institute of Scientific and Technical Information of China (English)

    Guo-fa WANG

    2013-01-01

    The paper introduced complete sets of automatic equipment and technology used in thin seam coal face,and proposed the comprehensive mechanization and automation of safe and high efficiency mining models based on the thin seam drum shearer.The key technology of short length and high power thin seam drum shearer,and new type roof support with big extension ratio and plate canopy were introduced.The new research achievement on automatic control system of complete sets of equipment for the thin seam coal,which composed of electronic-hydraulic system,compact thin seam roof supports,high effective shearer with intelligent control system,and characterized by automatical follow-up and remote control technology,was described in this paper..

  12. Permeability variation characteristics of coal after injecting carbon dioxide into a coal seam

    Institute of Scientific and Technical Information of China (English)

    Ni Xiaoming; Li Quanzhong; Wang Yanbin; Gao Shasha

    2015-01-01

    A theoretical basis for the optimization of carbon dioxide injection parameters and the development of the drainage system can be provided by identifying the permeability change characteristic of coal and rock after injection of carbon dioxide into the coal seam. Sihe, Yuwu, and Changcun mines were used as research sites. Scanning electron microscopy and permeability instruments were used to measure coal properties such as permeability and surface structure of the coal samples at different pH values of carbon dioxide solution and over different timescales. The results show that the reaction between minerals in coal and carbonate solution exhibit positive and negative aspects of permeability-the dissolution reaction between carbonate minerals in coal and acid solution improves the conductivity of coal whilst, on the other hand, the clay minerals in the coal (mainly including montmorillonite, illite and kaolinite) exhibit expansion as a result of ion exchange with the H+in acid solution, which has a negative effect on the per-meability of the coal. The permeability of coal samples increased at first and then decreased with immer-sion time, and when the soaking time is 2–3 months the permeability of the coal reached a maximum. In general, for coals with permeabilities less than 0.2 mD or greater than 2 mD, the effect on the permeabil-ity is low;when the permeability of the coal is in the range 0.2–2 mD, the effect on the permeability is highest. Research into permeability change characteristics can provide a theoretical basis for carbon diox-ide injection under different reservoir permeability conditions and subsequent drainage.

  13. Experimental Study on the Feasibility of Methane Drainage in Coal Seams with Compound Technique of Perforating and Fracturing

    Institute of Scientific and Technical Information of China (English)

    Luo Yong; Shen Zhaowu

    2007-01-01

    Compound technique of perforating and fracturing can effectively control the perforating direction and the fracturing expansion. The feasibility of this technique used in fracturing coal seams is analyzed. In this paper, the experiments of perforating and fracturing are carried out on samples of coal and the experimental effects are satisfactory. Compound technique of perforating and fracturing is promising in coal seams.

  14. A method of determining the permeability coefficient of coal seam based on the permeability of loaded coal

    Institute of Scientific and Technical Information of China (English)

    Li Bo; Wei Jianping; Wang Kai; Li Peng; Wang Ke

    2014-01-01

    This study developed the equipment for thermo-fluid-solid coupling of methane-containing coal, and investigated the seepage character of loaded coal under different working conditions. Regarding the effective pressure as a variable, the variation characteristics of the gas permeability of loaded meth-ane-containing coal has been studied under the conditions of different confining pressures and pore pres-sures. The qualitative and quantitative relationship between effective stress and permeability of loaded methane-containing coal has been established, considering the adsorption of deformation, amount of pore gas compression and temperature variation. The results show that the permeability of coal samples decreases along with the increasing effective stress. Based on the Darcy law, the correlation equation between the effective stress and permeability coefficient of coal seam has been established by combining the permeability coefficient of loaded coal and effective stress. On the basis of experimental data, this equation is used for calculation, and the results are in accordance with the measured gas permeability coefficient of coal seam. In conclusion, this method can be accurate and convenient to determine the gas permeability coefficient of coal seam, and provide evidence for forecasting that of the deep coal seam.

  15. Hydraulic support stability control of fully mechanized top coal caving face with steep coal seams based on instable critical angle

    Institute of Scientific and Technical Information of China (English)

    TO Shi-hao; YUAN Yong; LI Nai-liang; DOU Feng-jin; WANG Fang-tian

    2008-01-01

    Analyzed the support instable mode of sliding, tripping, and so on, and believedthe key point of the support stability control of fully mechanized coal caving face with steepcoal seams was to maintain that the seam true angle was less than the hydraulic supportinstability critical angle. Through the layout of oblique face, the improvement of supportsetting load, the control of mining height and nonskid platform, the group support systemof end face, the advance optimization of conveyor and support, and the other control tech-nical measures, the true angle of the seam is reduced and the instable critical angle of thesupport is increased, the hydraulic support stability of fully mechanized coal caving facewith steep coal seams is effectively controlled.

  16. Mechanism of Rock Burst Occurrence in Specially Thick Coal Seam with Rock Parting

    Science.gov (United States)

    Wang, Jian-chao; Jiang, Fu-xing; Meng, Xiang-jun; Wang, Xu-you; Zhu, Si-tao; Feng, Yu

    2016-05-01

    Specially thick coal seam with complex construction, such as rock parting and alternative soft and hard coal, is called specially thick coal seam with rock parting (STCSRP), which easily leads to rock burst during mining. Based on the stress distribution of rock parting zone, this study investigated the mechanism, engineering discriminant conditions, prevention methods, and risk evaluation method of rock burst occurrence in STCSRP through setting up a mechanical model. The main conclusions of this study are as follows. (1) When the mining face moves closer to the rock parting zone, the original non-uniform stress of the rock parting zone and the advancing stress of the mining face are combined to intensify gradually the shearing action of coal near the mining face. When the shearing action reaches a certain degree, rock burst easily occurs near the mining face. (2) Rock burst occurrence in STCSRP is positively associated with mining depth, advancing stress concentration factor of the mining face, thickness of rock parting, bursting liability of coal, thickness ratio of rock parting to coal seam, and difference of elastic modulus between rock parting and coal, whereas negatively associated with shear strength. (3) Technologies of large-diameter drilling, coal seam water injection, and deep hole blasting can reduce advancing stress concentration factor, thickness of rock parting, and difference of elastic modulus between rock parting and coal to lower the risk of rock burst in STCSRP. (4) The research result was applied to evaluate and control the risk of rock burst occurrence in STCSRP.

  17. Permeability prediction in deep coal seam: a case study on the No. 3 coal seam of the Southern Qinshui Basin in China.

    Science.gov (United States)

    Guo, Pinkun; Cheng, Yuanping

    2013-01-01

    The coal permeability is an important parameter in mine methane control and coal bed methane (CBM) exploitation, which determines the practicability of methane extraction. Permeability prediction in deep coal seam plays a significant role in evaluating the practicability of CBM exploitation. The coal permeability depends on the coal fractures controlled by strata stress, gas pressure, and strata temperature which change with depth. The effect of the strata stress, gas pressure, and strata temperature on the coal (the coal matrix and fracture) under triaxial stress and strain conditions was studied. Then we got the change of coal porosity with strata stress, gas pressure, and strata temperature and established a coal permeability model under tri-axial stress and strain conditions. The permeability of the No. 3 coal seam of the Southern Qinshui Basin in China was predicted, which is consistent with that tested in the field. The effect of the sorption swelling on porosity (permeability) firstly increases rapidly and then slowly with the increase of depth. However, the effect of thermal expansion and effective stress compression on porosity (permeability) increases linearly with the increase of depth. The most effective way to improve the permeability in exploiting CBM or extracting methane is to reduce the effective stress.

  18. Permeability Prediction in Deep Coal Seam: A Case Study on the No. 3 Coal Seam of the Southern Qinshui Basin in China

    Directory of Open Access Journals (Sweden)

    Pinkun Guo

    2013-01-01

    Full Text Available The coal permeability is an important parameter in mine methane control and coal bed methane (CBM exploitation, which determines the practicability of methane extraction. Permeability prediction in deep coal seam plays a significant role in evaluating the practicability of CBM exploitation. The coal permeability depends on the coal fractures controlled by strata stress, gas pressure, and strata temperature which change with depth. The effect of the strata stress, gas pressure, and strata temperature on the coal (the coal matrix and fracture under triaxial stress and strain conditions was studied. Then we got the change of coal porosity with strata stress, gas pressure, and strata temperature and established a coal permeability model under tri-axial stress and strain conditions. The permeability of the No. 3 coal seam of the Southern Qinshui Basin in China was predicted, which is consistent with that tested in the field. The effect of the sorption swelling on porosity (permeability firstly increases rapidly and then slowly with the increase of depth. However, the effect of thermal expansion and effective stress compression on porosity (permeability increases linearly with the increase of depth. The most effective way to improve the permeability in exploiting CBM or extracting methane is to reduce the effective stress.

  19. Law of surface movement for multi-coal seam strip mining 

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-ya; ZHANG Hong-mei

    2014-01-01

    It is an important part of green mining to control the disasters of coal mining which have caused irreversible damages to buildings and ecological environment. Strip mining is one of the efficient measures to control surface subsidence and mining damage. However, the research on the laws of the surface subsidence are still deficient in multi-coal seam strip mining at present. Based on the Fast Lagrangian Analysis of Continua (short for FLAC3D) numerical simulation software, the laws of the surface subsidence and horizontal movement were systematically studied for different depths, different mining widths, different distances between seams, different mining thickness, different parameters between seams and the special relations of the upper pillar and the lower pillar in the vertical direction in multi-seam strip mining. The function relation between the maximum subsidence and the maximum horizontal movement with the depth, the mining width, the seam distance, mining thickness, different parameters between seams and the partial offset are summarized respectively. Finally the formula integrating the surface maximum subsidence value and the maximum horizontal movement was deduced. The results can be used for reference theory and measure in forecasting the surface displacement in multi-coal seam strip mining.

  20. Applicable conditions for a classification system of aquifer-protective mining in hallow coal seams

    Institute of Scientific and Technical Information of China (English)

    Liu Yude; Zhang Dongsheng; Fan Gangwei; Yan Shoufeng

    2011-01-01

    Based on the conclusions of domestic and foreign research,we have analyzed the collapse-fall characteristics of overlying strata and the mechanism of aquifer-protective mining in shallow coal seam working faces at the Shendong Mine.We have selected the height of the water-conducting fracture zone in overlying strata as a composite index and established the applicable conditions of aquifer-protective mining in shallow coal seams with a multi-factor synthetic-index classification method.From our calculations and analyses of variance,we used factors such as the overlying strata strength,mining disturbing factors and rock integrity as related factors of the composite index.We have classified the applicable conditions of aquifer-protective mining in shallow coal seams into seven types by comparing the result of the height of water-conducting fractured zones of long-wall and short-wall working faces with the thickness of the bedrock.the thickness of the weathered zone and the size of safety coal-rock pillars.As a result,we propose the preliminary classification system of aquifer-protective mining in shallow coal seams.It can provide a theoretical guidance for safe applications of aquifer-protective mining technology in shallow coal seams under similar conditions.

  1. Fuzzy Evaluation of Coal Seam Geological Condition of Fully-Mechanized Face in Ten-Million-Ton Mine

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on coal seam geological condition and mining technological characteristic in Jisan Mine, coal seam geological condition is quantitative evaluated by using fuzzy evaluation with the view of coal mining and coalface production. The structure and index system of evaluation factor, the membership functions and weights of evaluation factor, evaluation model and reliability in the coal seam geological conditions are expounded in detail. Eighty-two coalfaces which will be exploited is classified. All of these have provided a theoretical foundation for the selection of coal mining technology and for sustainable development of the coal mine.

  2. Numerical simulation and damage analysis of fissure field evolution law in a single coal seam mining

    Institute of Scientific and Technical Information of China (English)

    Feng; Gao; Xingguang; Liu; Chaofeng; Ge; Hongmei; Cheng

    2012-01-01

    Based on the different deformation and failure laws of coal and rock materials under tensile or compressive loads,the damage variable was defined to divide three phases from the damage and rupture point of view in order to reveal the fissured field evolution characteristics and spatial distribution of coal and rock in the single coal seam mining with low permeability and rich methane.According to the corresponding damage constitutive equations,the secondary development of the finite element program was completed.The fissures field evolution law of a coal mine with single coal seam mining was calculated and analyzed by this new program and the distribution areas and failure degree of the surrounding coal and rock structures with damage,fissure or rupture are given on the condition of mining.This paper provides a scientific basis for quantitative research and evaluation of the safe simultaneous production of coal and gas.

  3. Test studies of gas flow in rock and coal surrounding a mined coal seam

    Institute of Scientific and Technical Information of China (English)

    Lv Youchang

    2012-01-01

    An analysis of the variation rule of abutment pressure at the mining working face in a single coal seam and the mechanical behavior of surrounding rock during stoping is presented.Consideration of the elastic and plastic deformation zones that develop during the mining process allowed the determination of a relationship between horizontal stress and vertical stress.Based on this,a confined pressure unloading test was conducted by the use of the "gas-containing coal thermo-fluid-solid coupling 3-axis servo seepage" experimental apparatus.Thus,gas flow patterns in the elastic and plastic zones were derived from an experimental point of view.Darcy's law and the Klinkenberg effect were used to derive a gas flow equation for the elastic and plastic stress fields.The study of gas flow phenomena at the working face during coal mining is of great importance for the study of gas migration and enrichment oatterns.

  4. Exploration possibilities of Oligocene coal seams in the vicinity of Mogyorosbanya and Szarkaspuszta

    Energy Technology Data Exchange (ETDEWEB)

    Gidai, L.

    1986-01-01

    In the Dorog Basin (North Trabnsdanubia) the Oligocene coal seams lie in much smaller depths than the Eocene ones, thus the prospective coal reserves could be mined under less dangerous conditions (water inrush etc.). A review of the history of exploration is given together with the demonstration of the structural-tectonic position of the area in question. The distribution and extension as well as the quality and thickness of the Oligocene coal seams are discussed with special reference to the strata columns. Eight regions are distinguished that may be suitable for economic use.

  5. Hydraulic Flushing Technology and Its Practice in Outburst Coal Seam with High Gas and Low Permeability

    Directory of Open Access Journals (Sweden)

    Qing Ye

    2015-10-01

    Full Text Available Hydraulic flushing technology can rapidly and effectively eliminate coal and gas outbursts and improve the permeability of a coal seam. Its effect mainly depends on the technical parameters of hydraulic flushing. To solve the problems on technical parameters that exist in the application of hydraulic flushing technology, the outburst elimination mechanism of hydraulic flushing technology was expatiated, the hydraulic flushing process was introduced, and a field test was performed on the B1 coal seam in Yi’an Coal Mine by using the pressure drop method. Moreover, the effective influence radius of hydraulic flushing measure was determined, and the technical parameters were analyzed. Finally, a series of relationships was obtained, including the relationships between hydraulic pressure and coal output, critical breaking coal pressure and firmness coefficient, flushing time and coal output, drilling hole angle and coal output, and coal output and effective influence radius. Results showed that the effective influence radius of hydraulic flushing in B1 coal seam was 9 m, and the outburst risk of the coal within the influence region was eliminated. In addition, the time of outburst elimination was shortened and the production rate was improved. The research results could provide technical support for the optimization of the technical parameters and the test scheme of hydraulic flushing measures.

  6. Dynamic failure in coal seams:Implications of coal composition for bump susceptibility

    Institute of Scientific and Technical Information of China (English)

    Lawson Heather; Weakley Andrew; Miller Arthur

    2016-01-01

    As a contributing factor in the dynamic failure (bumping) of coal pillars, a bump-prone coal seam has been described as one that is ‘uncleated or poorly cleated, strong. . .that sustains high stresses.”Despite extensive research regarding engineering controls to help reduce the risk for coal bumps, there is a paucity of research related to the properties of coal itself and how those properties might contribute to the mechanics of failures. Geographic distribution of reportable dynamic failure events reveals a highly localized clustering of incidents despite widespread mining activities. This suggests that unique, contributing geologic characteristics exist within these regions that are less prevalent elsewhere. To investigate a new approach for identifying coal characteristics that might lead to bumping, a principal component analysis (PCA) was performed on 306 coal records from the Pennsylvania State Coal Sample database to determine which characteristics were most closely linked with a positive history of reportable bumping. Selected material properties from the data records for coal samples were chosen as variables for the PCA and included petrographic, elemental, and molecular properties. Results of the PCA suggest a clear correlation between low organic sulfur content and the occurrence of dynamic failure, and a secondary correlation between volatile matter and dynamic failure phenomena. The ratio of vola-tile matter to sulfur in the samples shows strong correlation with bump-prone regions, with a minimum threshold value of approximately 20, while correlations determined for other petrographic and elemental variables were more ambiguous. Results suggest that the composition of the coal itself is directly linked to how likely a coal is to have experienced a reportable dynamic failure event. These compositional controls are distinct from other previously established engineering and geologic criteria and represent a missing piece to the bump prediction puzzle.

  7. Polymer Drilling Fluid with Micron-Grade Cenosphere for Deep Coal Seam

    Directory of Open Access Journals (Sweden)

    Peng Xu

    2015-01-01

    Full Text Available Traditional shallow coal seam uses clean water, solid-free system, and foam system as drilling fluid, while they are not suitable for deep coal seam drilling due to mismatching density, insufficient bearing capacity, and poor reservoir protection effect. According to the existing problems of drilling fluid, micron-grade cenosphere with high bearing capacity and ultralow true density is selected as density regulator; it, together with polymer “XC + CMC” and some other auxiliary agents, is jointly used to build micron-grade polymer drilling fluid with cenosphere which is suitable for deep coal seam. Basic performance test shows that the drilling fluid has good rheological property, low filtration loss, good density adjustability, shear thinning, and thixotropy; besides, drilling fluid flow is in line with the power law rheological model. Compared with traditional drilling fluid, dispersion stability basically does not change within 26 h; settlement stability evaluated with two methods only shows a small amount of change; permeability recovery rate evaluated with Qinshui Basin deep coal seam core exceeds 80%. Polymer drilling fluid with cenosphere provides a new thought to solve the problem of drilling fluid density and pressure for deep coal seam drilling and also effectively improves the performance of reservoir protection ability.

  8. Research on Protective Area of Exploiting Lower Protective Coal Seam and its Feasibility

    Directory of Open Access Journals (Sweden)

    Wang Kai

    2014-02-01

    Full Text Available Based on the reasonable consideration of the role of the second main stress in D-P criterion, the distribution of stress and deformation with the method of finite difference was simulated. And the stress relief angles along incline and strike according to the rules of stress and deformation were obtained. Then the protective area resulted from exploiting the lower protective coal seam were acquired. The results show that the stress relief angles along incline are 75.5 and 77.7 degrees, the ones along strike are 78.4 and 83.5 degrees in the sense of protection when the advancing distance is 300m. But the real effective protective area is much smaller. The largest degree of stress relief locates in the protected coal seam corresponding to the upper and middle of the working face. According the simulation results and the water inrush coefficient method of effective water-resisting seam, the water inrush risk area of lower protective coal seam was divided, and the feasibility of exploiting protective coal seam was analysed and judged. Research results are of certain guidance and reference significance in the layout of mining and gas extraction for the similar coal mines.

  9. Rapid pyrolysis of Serbian soft brown coals

    Energy Technology Data Exchange (ETDEWEB)

    Goran G. Jankes; Olga Cvetkovic; Nebojsa M. Milovanovic; Marko Ercegovaci Ercegovac; Miroljub Adzic; Mirjana Stamenic [University of Belgrade, Belgrade (Serbia). Faculty of Mechanical Engineering

    2009-07-01

    Soft brown coals of the open coal fields of Kolubara and Kostolac are the main domestic energy sources of Serbia. This paper presents the results of investigations on rapid devolatilization of these two coals which have covered kinetics of devolatilization (based on total volatile yield), forms of sulphur and petrographic analysis of coal and char. Experiments of devolatilization were performed in inert gas (N{sub 2}) at atmospheric pressure and in batch-type hot-wire screen reactor. The mass-loss values of both coals at selected final reaction temperatures (300-900{sup o}C) and retention times (3-28 s) were obtained. Anthony and Howard's kinetic model was applied over two temperature ranges (300-500 and 700-900{sup o}C). The types of sulphur as monosulphide, sulphate, pyritic, and organic sulphur were determined for chars and original coals. Strong transformation of pyrite was evident even at low temperatures (300{sup o}C). Devolatilization of all types of sulphur has started over 600 and at 900{sup o}C the content of sulphur in char remained only 66% of total sulphur in original coal. Microscopic investigations were carried out on samples prepared for reflected light measurements. The petrographic analysis included: the ratio of unchanged and changed coal, maceral types, the share of cenospheres, isotropic mixed carbonized grains, mixed grains, small fragments, clay, and pyrite. The change of the structure of devolatilized coal was also observed. 20 refs., 10 figs., 6 tabs.

  10. Principle and engineering application of pressure relief gas drainage in low permeability outburst coal seam

    Institute of Scientific and Technical Information of China (English)

    LIU lin; CHENG Yuan-ping; WANG Hai-feng; WANG Liang; MA Xian-qin

    2009-01-01

    With the increase in mining depth, the danger of coal and gas outbursts increases. In order to drain coal gas effectively and to eliminate the risk of coal and gas outbursts, we used a specific number of penetration boreholes for draining of pressure relief gas. Based on the principle of overlying strata movement, deformation and pressure relief, a good effect of gas drainage was obtained. The practice in the Panyi coal mine has shown that, after mining the Cllcoal seam as the protective layer, the relative expansion deformation value of the protected layer C13 reached 2.63%, The permeability coefficient increased 2880 times, the gas drainage rate of the C13 coal seam increased to more than 60%, the amount of gas was reduced from 13.0 to 5.2 m3/t and the gas pressure declined from 4.4 to 0.4 MPa, which caused the danger the outbursts in the coal seams to be eliminated. The result was that we achieved a safe and highly efficient mining operation of the C 13 coal seam.

  11. Organic geochemical study of sequences overlying coal seams: example from the Mansfield Formation (Lower Pennsylvania), Indiana

    Energy Technology Data Exchange (ETDEWEB)

    Mastalerz, M.; Stankiewicz, A.B.; Salmon, G.; Kvale, E.P.; Millard, C.L. [Indiana University, Bloomington, IN (United States). Indiana Geological Survey

    1997-09-01

    Roof successions above two coal seams from the Mansfield Formation (Lower Pennsylvanian) in the Indiana portion of the Illinois basin were studied with regard to sedimentary structures, organic petrology and organic geochemistry. The succession above the Blue Creek Member of the Mansfield Formation is typical of the lithologies covering low-sulphur coals ({lt} 1%) in the area studied, whereas the succession above the unnamed Mansfield coal is typical of high-sulphur coal({gt} 2%). The transgressive-regressive packages above both seams reflect the periodic inundation of coastal mires by tidal flats and creeks. Geochemistry and petrology of organic facies above the Blue Creek coal suggest that tidal flats formed inland in fresh-water environments. Above the unnamed coal, trace fossils and geochemical and petrological characteristics of organic facies suggest more unrestricted seaward depositional. 55 refs., 11 figs., 3 tabs.

  12. Adult Education and Radical Habitus in an Environmental Campaign: Learning in the Coal Seam Gas Protests in Australia

    Science.gov (United States)

    Ollis, Tracey; Hamel-Green, Michael

    2015-01-01

    This paper examines the adult learning dimensions of protestors as they participate in a campaign to stop coal seam gas exploration in Gippsland in Central Victoria, Australia. On a global level, the imposition of coal seam gas exploration by governments and mining companies has been the trigger for movements of resistance from environmental…

  13. Geomechanics of subsidence above single and multi-seam coal mining

    Institute of Scientific and Technical Information of China (English)

    A.M. Suchowerska Iwanec; J.P. Carter; J.P. Hambleton

    2016-01-01

    Accurate prediction of surface subsidence due to the extraction of underground coal seams is a significant challenge in geotechnical engineering. This task is further compounded by the growing trend for coal to be extracted from seams either above or below previously extracted coal seams, a practice known as multi-seam mining. In order to accurately predict the subsidence above single and multi-seam longwall panels using numerical methods, constitutive laws need to appropriately represent the mechanical behaviour of coal measure strata. The choice of the most appropriate model is not always straightforward. This paper compares predictions of surface subsidence obtained using the finite element method, considering a range of well-known constitutive models. The results show that more sophisticated and numerically taxing constitutive laws do not necessarily lead to more accurate predictions of subsidence when compared to field measurements. The advantages and limitations of using each particular constitutive law are discussed. A comparison of the numerical predictions and field measurements of surface subsidence is also provided.

  14. Geomechanics of subsidence above single and multi-seam coal mining

    Directory of Open Access Journals (Sweden)

    A.M. Suchowerska Iwanec

    2016-06-01

    Full Text Available Accurate prediction of surface subsidence due to the extraction of underground coal seams is a significant challenge in geotechnical engineering. This task is further compounded by the growing trend for coal to be extracted from seams either above or below previously extracted coal seams, a practice known as multi-seam mining. In order to accurately predict the subsidence above single and multi-seam longwall panels using numerical methods, constitutive laws need to appropriately represent the mechanical behaviour of coal measure strata. The choice of the most appropriate model is not always straightforward. This paper compares predictions of surface subsidence obtained using the finite element method, considering a range of well-known constitutive models. The results show that more sophisticated and numerically taxing constitutive laws do not necessarily lead to more accurate predictions of subsidence when compared to field measurements. The advantages and limitations of using each particular constitutive law are discussed. A comparison of the numerical predictions and field measurements of surface subsidence is also provided.

  15. Methane conditions in the coal seam of the Stara Jama mine in Zenica. Metanonosnost - Gasonosnost ugljenog sloja Stara Jama Zenica

    Energy Technology Data Exchange (ETDEWEB)

    Adilovic, A.; Micevic, S. (Rudarski Institut, Tuzla (Yugoslavia))

    1990-01-01

    Reviews methane emission at the Stara Jama underground coal mine in the Zenica coal basin (Yugoslavia). Geologic and tectonic conditions of the mine are described, as well as the mechanized longwall mining and mine ventilation system. Sorption properties of the coal seam in 11.7 m mean thickness were determined, methane released from the coal seam was measured by a special container, a manometer and the AOP-1 vacuum apparatus. Methane losses during the sampling procedure were taken into account. Measurement results for the upper, medium and lower sections of the coal seam are presented separately in a table. An average methane content of 3.5 m{sup 3}/t of coal in intact coal seams was determined. 4 refs.

  16. Assessment of uncertainty and degasification efficiency in coal seam gas drainage through stochastic reservoir simulation

    Science.gov (United States)

    Özgen Karacan, C.

    2016-04-01

    Coal seam degasification improves coal mine safety by reducing the gas content of coal seams and also by generating added value as an energy source. Coal bed reservoir simulation, as a reservoir management and forecasting tool, is one of the most effective ways to help with these two main objectives. However, as in all modeling and simulation studies, reservoir description and whether observed productions can be predicted are important considerations. Using geostatistical realizations as spatial maps of different coal reservoir properties is a more realistic approach than assuming uniform properties across the field. In fact, this approach can help with simultaneous history matching of multiple wellbores to enhance the confidence in spatial models of different coal properties that are pertinent to degasification. The problem that still remains, however, is the uncertainty in geostatistical, and thus reservoir, simulations originating from partial sampling of the seam that does not properly reflect the stochastic nature of coal property realizations. This study demonstrates the use of geostatistical realizations generated through sequential Gaussian simulation and co-simulation techniques and assesses the uncertainty in coal seam reservoir simulations with history matching errors. 100 individual realizations of 10 coal properties were generated using geostatistical techniques. These realizations were used to create 100 realization bundles (property datasets). Each of these bundles was then used in coal seam reservoir simulations for simultaneous history matching of degasification wells. History matching errors for each bundle were evaluated and the single set of realizations that would minimize the error for all wells was defined. Errors were compared with those of E-type and the average realization of the best matches. The study helped to determine the realization bundle that consisted of the spatial maps of coal properties, which resulted in minimum error. In

  17. Thermodestruction of brown coals of different genetic types

    Energy Technology Data Exchange (ETDEWEB)

    Butuzova, Ludmila; Isaeva, Lubov [L.M. Litvinenko Institute of Physical Organic and Coal Chemistry, National Academy of Sciences of the Ukraine, 70 R. Luxemburg str., 83114 Donetsk (Ukraine); Turchanina, Oksana [Donetsk National Technical University, 48 Artema str., 83000 Donetsk (Ukraine); Krzton, Andrzej [Institute of Coal Chemistry, Polish Academy of Sciences, 5 Sowinskiego, 44-102, Gliwice (Poland)

    2002-06-20

    The influence of brown coal genetic type and method of chemical pre-treatment on its behavior in pyrolysis processes has been shown. An important role of brown coal reductivity in coal thermal decomposition has been ascertained. It has been found that chemical pre-treatment permits variation of the rate of pyrolysis, the yields of pyrolysis products and structure of semi-cokes.

  18. Molecular characterization of microbial communities in deep coal seam groundwater of northern Japan

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, S.; Akiyama, M.; Naganuma, T.; Fujioka, M.; Nako, M.; Ishijima, Y. [Northern Advancement Center for Science and Technology, Hokkaido (Japan)

    2007-12-15

    We investigated microbial methanogenesis and community structure based on 16S rRNA gene sequences from a coal seam aquifer located 843-907 m below ground level in northern Japan; additionally, we studied the {delta}{sup 13}C and {delta} {sup 2}H ({delta}D) of coal-bed gases and other physicochemical parameters. Although isotopic analysis suggested a thermocatalytic origin for the gases, the microbial activity and community structure strongly implied the existence of methanogenic microbial communities in situ. Methane was generated in the enrichment cultures of the hydrogenotrophic and methylotrophic microorganisms obtained from coal seam groundwater. Methanogen clones dominated the archaeal 16S rRNA gene libraries and were mostly related to the hydrogenotrophic genus Methanoculleus and the methylotrophic genus Methanolobus. Bacterial 16S rRNA gene libraries were dominated by the clones related to the genera Acetobacterium and Syntrophus which have a symbiotic association with methanogens. LIBSHUFF analysis revealed that N{sub 2} gas injected into the coal seam (for enhanced methane production) does not affect the coverage of archaeal and bacterial populations. However, AMOVA analysis does provide evidence for a change in the genetic diversity of archaeal populations that are dominated by methanogens. Therefore, N{sub 2} injection into the coal seam might affect the cycling of matter by methanogens in situ.

  19. Forward Modeling of Azimuthal Anisotropy to the Reflected P Wave of Coal Seam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-gong; DONG Shou-hua; YUE Jian-hua

    2006-01-01

    Under the condition of weak anisotropy, the relation of P-wave anisotropy in direction to fractures of coal seams was researched in order to forecast the density and the direction of the fractures. Although the approximate solution by Rüger is suitable for thick reservoirs, it has some limitations for the composite reflected wave from both roofs and floors of coal seams, as well as multiple reflections. So first, the phase velocity and group velocity as well as their travel time were calculated about the reflected P-wave of the coal seam. Then, the anisotropic coefficients of both roofs and floors were calculated by Rüger formulae and last, the section versus azimuth in fixed offset can be gotten by convolution. In addition, the relation of amplitude of the composite reflected wave to azimuth angle was discussed. The forward modelling results of the coal azimuth anisotropy show these: 1) the coal seam is the strong reflecting layer, but the change of the reflectivity caused by the azimuth anisotropy is smaller; 2) if the azimuth angle is parallel to the crack strike, the reflectivity reaches up to the maximum absolute value, however, if the azimuth angle is perpendicular to the crack strike, the absolute value of the reflection coefficient is minimum; and 3)the reflection coefficient is the cosine function of the azimuth angle and the period is π.

  20. A poromechanical model for coal seams saturated with binary mixtures of CH4 and CO2

    Science.gov (United States)

    Nikoosokhan, Saeid; Vandamme, Matthieu; Dangla, Patrick

    2014-11-01

    Underground coal bed reservoirs naturally contain methane which can be produced. In parallel of the production of this methane, carbon dioxide can be injected, either to enhance the production of methane, or to have this carbon dioxide stored over geological periods of time. As a prerequisite to any simulation of an Enhanced Coal Bed Methane recovery process (ECBM), we need state equations to model the behavior of the seam when cleats are saturated with a miscible mixture of CH4 and CO2. This paper presents a poromechanical model of coal seams exposed to such binary mixtures filling both the cleats in the seam and the porosity of the coal matrix. This model is an extension of a previous work which dealt with pure fluid. Special care is dedicated to keep the model consistent thermodynamically. The model is fully calibrated with a mix of experimental data and numerical data from molecular simulations. Predicting variations of porosity or permeability requires only calibration based on swelling data. With the calibrated state equations, we predict numerically how porosity, permeability, and adsorbed amounts of fluid vary in a representative volume element of coal seam in isochoric or oedometric conditions, as a function of the pressure and of the composition of the fluid in the cleats.

  1. Dynamic effects of high-pressure pulsed water jet in low-permeability coal seams

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-hong; ZHOU Dong-ping; LU Yi-yu; KANG Yong; ZHAO Yu; WANG Xiao-chuan

    2009-01-01

    Mine gas extraction in China is difficult due to the characteristics such as mi-cro-porosity, low-permeability and high adsorption of coal seams. The pulsed mechanism of a high-pressure pulsed water jet was studied through theoretical analysis, experiment and field measurement. The results show that high-pressure pulsed water jet has three dynamic properties. What's more, the three dynamic effects can be found in low-perme-ability coal seams. A new pulsed water jet with 200-1 000 Hz oscillation frequency and peak pressure 2.5 times than average pressure was introduced. During bubble collapsing, sound vibration and instantaneous high pressures over 100 MPa enhanced the cutting ability of the high-pressure jet. Through high-pressure pulsed water jet drilling and slotting, the exposure area of coal bodies was greatly enlarged and pressure of the coal seams rapidly decreased. Therefore, the permeability of coal seams was improved and gas ab-sorption rate also decreased. Application results show that gas adsorption rate decreased by 30%-40% and the penetrability coefficient increased 100 times. This proves that high-pressure pulsed water is more efficient than other conventional methods.

  2. Determining areas in an inclined coal seam floor prone to water-inrush by micro-seismic monitoring

    Institute of Scientific and Technical Information of China (English)

    Sun Jian; Wang Lianguo; Wang Zhansheng; Hou Huaqiang; Shen Yifeng

    2011-01-01

    The failure depth of the coal seam floor is one important consideration that must be kept in mind when mining is carried out above a confined aquifer. Determining the floor failure depth is the essential precondition for predicting the water-resisting ability of the floor. We have used a high-precision microseismic monitoring technique to overcome the limited amount of data available from field measurements. The failure depth of a coal seam floor, especially an inclined coal seam floor, may be more accurately estimated by monitoring the continuous, dynamic failure of the floor. The monitoring results indicate the failure depth of the coal seam floor near the workface conveyance roadway (the lower crossheading) is deeper and that the failure range is wider here compared to the coal seam floor near the return airway (the upper crossheading). The results of micro-seismic monitoring show that the dangerous area for water-inrush from the coal seam floor may be identified. This provides an important field measurement that helps ensure safe and highly efficient mining of the inclined coal seam above the confined aquifer at the Taoyuan Coal Mine.

  3. Planning of excavation of seams characterized by complicated structure with the aim of coal mixing

    Energy Technology Data Exchange (ETDEWEB)

    Belyakov, Yu.I.; Pushkin, S.P. (Kievskii Inzhenerno-Stroitel' nyi Institut (USSR))

    1990-07-01

    Discusses use of mathematical modeling for optimization of surface mining in mines with a complicated coal deposit structure and changing coal quality. The modeling is aimed at stabilizing coal quality, especially ash content. Surface mines with bucket wheel excavators for overburden removal and mining and locomotives and railroad cars for mine haulage are modeled. The mines supply 2 classes of coal: with 47% ash and with 55%. The modeling is aimed at determining optimum advance rates of the bucket wheel excavators. Effects of mine haulage system, coal yard capacity, coal seam structure, fluctuations of coal quality in a coal deposit, requirements for optimum geometry of the working faces, benches and other elements that influence slope stability are considered. 2 refs.

  4. In-situ coal seam and overburden permeability characterization combining downhole flow meter and temperature logs.

    Directory of Open Access Journals (Sweden)

    Busse Julia

    2016-06-01

    Full Text Available The planning and design of any coal mine development requires among others a thorough investigation of the geological, geotechnical and hydrogeological subsurface conditions. As part of a coal mine exploration program we conducted heat pulse vertical flow meter testing. The flow data were combined with absolute and differential temperature logging data to gain information about the hydraulic characteristics of two different coal seams and their over- and interburden. For the strata that were localised based on geophysical logging data including density, gamma ray and resistivity hydraulic properties were quantified. We demonstrate that the temperature log response complements the flow meter log response. A coupling of both methods is therefore recommended to get an insight into the hydraulic conditions in a coal seam and its overburden.

  5. Comparison of outburst danger criteria of coal seams for acoustic spectral and instrumental forecast methods

    Science.gov (United States)

    Shadrin, A. V.; Bireva, Yu A.

    2016-10-01

    Outburst danger criteria for the two methods of current coal seam outburst forecast are considered: instrumental - by the initial outgassing rate and chippings outlet during test boreholes drilling, and geo-physical - by relation of high frequency and low frequency components of noise caused by cutting tool of operating equipment probing the face area taking into consideration the outburst criteria correction based on methane concentration at the face area and the coal strength. The conclusion is made on “adjustment” possibility of acoustic spectral forecast method criterion amended by control of methane concentration at the coal face and the coal strength taken from the instrumental method forecast results.

  6. Installed capacity of coal seam gas power generation exceeds 480 MW under SGCC s coverage

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The journalist learned from the "National Gas Security Working Conference" held recently that the coal seam gas power generation has been rapidly developed in recent years.As of July 2009,within the SGCC's business area,the power generation units

  7. Fully mechanised working of vertical and thin coal seams in the Central Asturian coalfield

    Energy Technology Data Exchange (ETDEWEB)

    Arsuaga, J.; Luque, V.; Garcia Arguelles, A.; Beckmann, K.

    1984-01-01

    This describes integrated mechanisation trials on a coal face in a thin vertical seam with geological irregularities. The mining company used a shearer of its own design, HUNOSA-1, and Westfalia-Lunen and Mackina Westfalia hydraulically powered supports. Excellent results were obtained.

  8. Seam-wave measurements in the pits of Nogrod coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Toros, E.; Bodoky, T.

    1988-01-01

    The principle of measuring seismic seam-waves is shortly reviewed and measurement examples are given from the coal mines of Nograd County. Reflection measurements and time sections are exemplified by different figures from different pits. The preliminary results of the method obtained in these mines as well as further application possibilities of the method are described.

  9. Origin of banded structure and coal lithotype cycles in Kargali coal seam of East Bokaro sub-basin, Jharkhand, India: Environmental implications

    Indian Academy of Sciences (India)

    Ram Chandra Tewari; Zahid A Khan

    2015-04-01

    The Kargali seam of Early Permian Barakar cyclothems of East Bokaro sub-basin of Jharkhand, India is 12–30 m thick, splits into two parts, and extends throughout the length of the basin. It is made up of interbedded sequences and variable proportions of Vitrain, Clarain, Durain and Fusain. Application of embedded Markov chain model rejects the phenomenon of randomness in the repetition of coal lithotypes. The preferential upward transition path for coal lithotypes that can be derived for the Kargali top coal seam is: Vitrain → Clarain → Durain ↔ Fusain → Vitrain, and for the Kargali bottom coal seam is: Clarain ↔ Vitrain → Fusain → Durain → Clarain. By and large, the cyclic repetition of coal lithotypes is similar in the Kargali bottom and top seams. Among the noteworthy features are two-way transitions between Durain and Fusian in Kargali top and between Clarain and Vitrain in the case of Kargali bottom coal seam. Entropy analysis corroborates Markov chain and indicates the presence of type A-4 asymmetrical cycles of coal lithotypes. It is suggested that the banded structure of a coal seam is not a random feature and follows a definite cyclic pattern in the occurrence of coal lithotypes in vertical order and is similar to that described in Australian and European coal seams. Asymmetrical cyclic sequences are a normal, rather than an unusual condition, within coal seams. It is visualized that a gradual decline of toxic environment and ground water level resulted in the coal lithotype cycles in the Kargali seam of East Bokaro sub-basin. The close interbedding of Vitrain and Clarain is suggestive of seasonal fluctuation in anaerobic and aerobic conditions during peat formation.

  10. Element geochemistry and cleaning potential of the No. 11 coal seam from Antaibao mining district

    Institute of Scientific and Technical Information of China (English)

    WANG; Wenfeng; QIN; Yong; SONG; Dangyu; SANG; Shuxun; JIAN

    2005-01-01

    Based on the analyses of sulfur and 41 other elements in 8 channel samples of the No. 11 coal seam from Antaibao surface mine, Shanxi, China and 4 samples from the coal preparation plant of this mine, the distribution of the elements in the seam profile, their geochemical partitioning behavior during the coal cleaning and the genetic relationships between the both are studied. The conclusions are drawn as follows. The coal-forming environment was probably invaded by sea water during the post-stage of peatification, which results in the fact that the contents of As, Fe, S, etc. associated closely with sea water tend to increase toward the top of the seam, and that the kaolinite changes into illite and montmorillonite in the coal-sublayer near the roof. These elements studied are dominantly associated with kaolinite, pyrite, illite, montmorillonite, etc., of which the As, Pb, Mn, Cs, Co, Ni, etc. are mainly associated with sulfides, the Mo, V, Nb, Hf, REEs, Ta etc. mainly with kaolintie, the Mg, Al etc. mainly with epigenetic montmorillonite, and the Rb, Cr, Ba, Cu, K, Hg, etc. mainly with epigenetic illite. The physical coal cleaning is not only effective in the removal of ash and sulfur, but also in reducing the concentration of most major and trace elements. The elements Be, U, Sb, W, Br, Se, P, etc. are largely or partly organically bound showing a relatively low removability, while the removability of the other elements studied is more than 20%, of which the Mg, Mn, Hg, Fe, As, K, Al, Cs, and Cr associated mostly with the coarser or epigenetic minerals show a higher removability than that of ash. The distribution of the elements in the seam profile controls their partitioning behavior to a great degree during the coal cleaning processes.

  11. Study on the non-linear forecast method for water inrush from coal seam floor based on wavelet neural network

    Institute of Scientific and Technical Information of China (English)

    ZHOU Rong-yi; LIU Ai-qun; LI Shu-qing

    2007-01-01

    Directing at the non-linear dynamic characteristics of water inrush from coal seam floor and by the analysis of the shortages of current forecast methods for water inrush from coal seam floor,a new forecast method was raised based on wavelet neural network(WNN)that was a model combining wavelet function with artificiaI neural network.Firstly basic principle of WNN was described.then a forecast model for water inrush from coal seam floor based on WNN was established and analyzed,finally an example of forecasting the quantity of water inrush from coal floor was illustrated to verify the feasibility and superiority of this method.Conclusions show that the forecast result based on WNN is more precise and that using WNN model to forecast the quantity of water inrush from coal seam floor is feasible and practical.

  12. Coal petrology of coal seams from the Leao-Butia Coalfield, Lower Permian of the Parana Basin, Brazil - Implications for coal facies interpretations

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.B. [Laboratorio de Oceanografia Geologica, Departamento de Geociencias, Fundacao Universidade Federal do Rio Grande, FURG, Av. Italia km 08, Campus Carreiros, 96201-900, Rio Grande, RS (Brazil); Kalkreuth, W.; Holz, M. [Instituto de Geociencias, UFRGS, Av. Bento Goncalves, 9500 91501-970 Porto Alegre, RS (Brazil)

    2008-02-01

    In the Leao-Butia Coalfield, Rio Grande do Sul the coal seams occur in the Rio Bonito Formation, Guata Group, Tubarao Supergroup of the Parana Basin, Brazil and are of Permian (Artinskian-Kungurian) age. This study is the first detailed investigation on the coal petrographic characterization of the coal-bearing sequence in relation to the depositional settings of the precursor mires, both in terms of whole seam characterization and in-seam variations. The study is based on the analyses of nine coal seams (I2, CI, L4, L3, L2, L1, S3, S2, S1), which were selected from core of borehole D-193, Leao-Butia and represent the entire coal-bearing sequence. The interpretation of coal facies and depositional environment is based on lithotype, maceral and microlithotype analyses using different facies-critical petrographic indices, which were displayed in coal facies diagrams. The seams are characterized by the predominance of dull lithotypes (dull, banded dull). The dullness of the coal is attributed to relatively high mineral matter, inertinite and liptinite contents. The petrographic composition is dominated by vitrinite (28-70 vol.% mmf) and inertinite (> 30 vol.% mmf) groups. Liptinite contents range from 7 to 30 vol.% (mmf) and mineral matter from 4-30 vol.%. Microlithotypes associations are dominated by vitrite, duroclarite, carbominerite and inertite. It is suggested that the observed vertical variations in petrographic characteristics (lithotypes, microlithotypes, macerals, vitrinite reflectance) were controlled by groundwater level fluctuations in the ancient mires due to different accommodation/peat accumulation rates. Correlation of the borehole strata with the general sequence-stratigraphical setting suggests that the alluvial fan system and the coal-bearing mudstone succession are linked to a late transgressive systems tract of sequence 2. Based on average compositional values obtained from coal facies diagrams, a deposition in a limno-telmatic to limnic coal

  13. Numerical investigations on mapping permeability heterogeneity in coal seam gas reservoirs using seismo-electric methods

    Science.gov (United States)

    Gross, L.; Shaw, S.

    2016-04-01

    Mapping the horizontal distribution of permeability is a key problem for the coal seam gas industry. Poststack seismic data with anisotropy attributes provide estimates for fracture density and orientation which are then interpreted in terms of permeability. This approach delivers an indirect measure of permeability and can fail if other sources of anisotropy (for instance stress) come into play. Seismo-electric methods, based on recording the electric signal from pore fluid movements stimulated through a seismic wave, measure permeability directly. In this paper we use numerical simulations to demonstrate that the seismo-electric method is potentially suitable to map the horizontal distribution of permeability changes across coal seams. We propose the use of an amplitude to offset (AVO) analysis of the electrical signal in combination with poststack seismic data collected during the exploration phase. Recording of electrical signals from a simple seismic source can be closer to production planning and operations. The numerical model is based on a sonic wave propagation model under the low frequency, saturated media assumption and uses a coupled high order spectral element and low order finite element solver. We investigate the impact of seam thickness, coal seam layering, layering in the overburden and horizontal heterogeneity of permeability.

  14. A New Accumulation Model of Coal Seams in France Extensional Basins

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper, based on the sedimentary features of the coal seams in the typical extensional (faulted) coal basins between two inland mountainous areas of the Central Massif (France) deals with the accumulation mechanism and the corresponding sedimentary-tectonic conditions of these thick coalbeds, and proposes a new coal accumulation model for the inland lacustrine-basin thick coalbeds. The presence of a great number of gravity-flow sediments such as detrital flow, diluted slurry flow or turbidity-current sediments in the coal seams, and that of the contemporaneous gravity slump and deformation structure in the coal seam itself bath indicate that thelacustrine environment in the accumulation of the thick coalbeds was characterized by the relatively deep flood and violent sedimentation. This model can not only interpret reasonably the accumulation mecha nism of the thick coalbeds developed in the fault basins in the Central Massif, France, but also show its features distinctively from those of the accumulation model of the traditional thick coalbeds.

  15. Guiding-controlling technology of coal seam hydraulic fracturing fractures extension

    Institute of Scientific and Technical Information of China (English)

    Zhai; Cheng; Li; Min; Sun; Chen; Zhang; Jianguo; Yang; Wei; Li; Quangui

    2012-01-01

    Aiming at the uncontrollable problem of extension direction of coal seam hydraulic fracturing,this study analyzed the course of fractures variation around the boreholes in process of hydraulic fracturing,and carried out the numerical simulations to investigate the effect of artificial predetermined fractures on stress distribution around fractured holes.The simulation results show that partial coal mass occurs relatively strong shear failure and forms weak surfaces,and then fractures extended along the desired direction while predetermined fractures changed stress distribution.Directional fracturing makes the fractures link up and the pressure on coal mass is relieved within fractured regions.Combining deep hole controlling blasting with hydraulic fracturing was proposed to realize the extension guiding-controlling technology of coal seam fractures.Industrial experiments prove that this technology can avoid local stress concentration and dramatically widen the pressure relief scope of deep hole controlling blasting.The permeability of fractured coal seam increased significantly,and gas extraction was greatly improved.Besides,regional pressure relief and permeability increase was achieved in this study.

  16. Impact of longwall mining on groundwater above the longwall panel in shallow coal seams

    Directory of Open Access Journals (Sweden)

    Yang Li

    2015-06-01

    Full Text Available Since longwall mining causes subsidence through the overlying strata to the ground surface, the surface water and groundwater above the longwall panels may be affected and drained into the lower levels. Therefore, loss or interruption of streams and overburden aquifers is a common concern in coal industry. This paper analyzed the potential effects of longwall mining on subsurface water system in shallow coal seam. In order to monitor different water level fluctuations throughout the mining period, three water wells were drilled down to the proposed deformation zone above the longwall panel. A GGU-SS-FLOW3D model was used to predict water table contours for the periods of pre- and post-mining conditions. The field data from the three water wells were utilized to calibrate the model. The field test and numerical model can help to better understand the dewatering of shallow aquifers and surface waters related to ground subsidence from longwall mining in shallow coal seam.

  17. Impact of longwall mining on groundwater above the longwall panel in shallow coal seams

    Institute of Scientific and Technical Information of China (English)

    Yang Li; Syd S. Peng; Jinwang Zhang

    2015-01-01

    Since longwall mining causes subsidence through the overlying strata to the ground surface, the surface water and groundwater above the longwall panels may be affected and drained into the lower levels. Therefore, loss or interruption of streams and overburden aquifers is a common concern in coal industry. This paper analyzed the potential effects of longwall mining on subsurface water system in shallow coal seam. In order to monitor different water level fluctuations throughout the mining period, three water wells were drilled down to the proposed deformation zone above the longwall panel. A GGU-SS-FLOW3D model was used to predict water table contours for the periods of pre-and post-mining conditions. The field data from the three water wells were utilized to calibrate the model. The field test and numerical model can help to better understand the dewatering of shallow aquifers and surface waters related to ground subsidence from longwall mining in shallow coal seam.

  18. Dynamic destabilization analysis based on AE experiment of deep-seated, steep-inclined and extra-thick coal seam

    Institute of Scientific and Technical Information of China (English)

    Fenhua Ren; Xingping Lai; Meifeng Cai

    2008-01-01

    No. 5 coal seam in Huating Coal Mine is a deep-seated, steep-inclined extra-thick coal seam where excavation disturbance is quite frequent. The maximum and minimum principal stresses differ widely. During mining, dynamical destabilization happens frequently and induce tragedies. Based on the comparison between the acoustic emission (AE) experiment on dynamical destabilization of coal rock and the related in situ testing results, this article provides comprehensive analysis on the regular quantificational AE patterns (energy rate, total events) of coal rock destabilization in complex-variable environment. The comparison parameters include dynamic tension energy rate, deformation resistance to compression, and shear stress.

  19. Investigation of exploiting thick coal seams and the possibilities of increasing the vertical concentration

    Energy Technology Data Exchange (ETDEWEB)

    Pera, F.

    1987-01-01

    In underground coal mines the efficiency of exploiting thick coal seams can be increased first of all by increasing the vertical concentration. The most suitable method can be chosen by simple modelling. In cases where both the natural and technical conditions allow the use of the sub-caving method on long-wall faces, and on the basis of comparisons between the technical and economic parameters, the method discussed can be recommended. The shield support system with single scraper and overhead tapping is one of the most adequate ones. The Hungarian made VHP 730 type shields provided good results in the Ajka coal fields.

  20. Layout and support design of a coal roadway in ultra-close multiple-seams

    Institute of Scientific and Technical Information of China (English)

    严红; 翁明月; 冯锐敏; 李伟康

    2015-01-01

    A roadway within ultra-close multiple-seams (RUCMSs) is one of the most difficult supported coal roadways to deal with in underground coal mines. This is usually due to the unknown stress distributions, improper roadway layout, and unreasonable support parameters. In order to solve this support problem and effectively save RUCMSs from frequent and abrupt disasters (such as serious deformation of the surrounding rock, roof cave ins, and coal side collapse), a comprehensive method is adopted here which includes theoretical analysis, numerical simulation, and field monitoring. A mechanical model was constructed to determine the stress distribution in the coal pillar after two sides of a longwall panel had been mined. Based on this model, the horizontal, vertical, and tangential stress equations for the plane below the floor of the upper-left coal pillar were deduced. In addition, a typical coal mine (the Jinggonger colliery, located in Shuozhou city, Shanxi province, China) with an average distance between its 9# and 11# coal seams of less than 8.0 was chosen to conduct research on the proper layout and reasonable support required for a typical coal roadway located within coal seam 11#. Using FLAC3D (Fast Lagrangian Analysis of Continua in 3-Dimensions) numerical software, eight schemes were designed with different horizontal distances (d) between the center lines of the coal pillar and the roadway in the lower coal seam (RLCS). The simulations and detailed analysis indicate that the proper distances required are between 22.5 and 27.5 m. A total of 20 simulation schemes were used to investigate the factors influencing the support provided by the key bolts (bolt length, spacing, distance between two rows, installation angle, and pre-tightening force). The results were analyzed and used to determine reasonable values for the support parameters. Field results show that the stability and strength of the RLCS can be effectively safeguarded using a combination of researched

  1. Layout and support design of a coal roadway in ultra-close multiple-seams

    Institute of Scientific and Technical Information of China (English)

    严红; 翁明月; 冯锐敏; 李伟康

    2015-01-01

    A roadway within ultra-close multiple-seams(RUCMSs) is one of the most difficult supported coal roadways to deal with in underground coal mines. This is usually due to the unknown stress distributions, improper roadway layout, and unreasonable support parameters. In order to solve this support problem and effectively save RUCMSs from frequent and abrupt disasters(such as serious deformation of the surrounding rock, roof cave ins, and coal side collapse), a comprehensive method is adopted here which includes theoretical analysis, numerical simulation, and field monitoring. A mechanical model was constructed to determine the stress distribution in the coal pillar after two sides of a longwall panel had been mined. Based on this model, the horizontal, vertical, and tangential stress equations for the plane below the floor of the upper-left coal pillar were deduced. In addition, a typical coal mine(the Jinggonger colliery, located in Shuozhou city, Shanxi province, China) with an average distance between its 9# and 11# coal seams of less than 8.0 was chosen to conduct research on the proper layout and reasonable support required for a typical coal roadway located within coal seam 11#. Using FLAC3D(Fast Lagrangian Analysis of Continua in 3-Dimensions) numerical software, eight schemes were designed with different horizontal distances(d) between the center lines of the coal pillar and the roadway in the lower coal seam(RLCS). The simulations and detailed analysis indicate that the proper distances required are between 22.5 and 27.5 m. A total of 20 simulation schemes were used to investigate the factors influencing the support provided by the key bolts(bolt length, spacing, distance between two rows, installation angle, and pre-tightening force). The results were analyzed and used to determine reasonable values for the support parameters. Field results show that the stability and strength of the RLCS can be effectively safeguarded using a combination of researched stress

  2. 论煤层的加积方式%On Accreation Pattern of Coal Seams

    Institute of Scientific and Technical Information of China (English)

    赵万福

    2012-01-01

    The origin of coal seams is the kernel of coal geology. Coal seam is a kind of sedimentary stratum, it adheres to the basic principles of the sedimentology, stratigraphy, petrology and study of ore deposits, but still has its particularity, and its origin differs from origin of coal. Classic kernel viewpoint of coal geology is coal seam evolving from peat bog; its essence is vertical accretion of coal-forming material. Through coal seam vertical and lateral accretions contrastive analyses and large area stable distributed thick coal seam low gamma-ray multi-crest phenomenon, sedimentary features of bedding and banded structure studies have considered that the coal-forming material is mechanically deposited, while coal seam likes most sedimentary strata is laterally accreted. As to thick coal seams, multi -stage lateral accretions bring on secondary vertical accretions; their formation process is not a simple, consecutive, linear vertical progressive process, but a rather complicated, inconsecutive, nonlinear lateral superimposed process. Coal-forming material is inconsecutive, multi -staged and multi -sourced, ubiquitous parting in thick coal seams is the evidence of inconsequence, moreover, thick coal seams are diachronous. Coal seam lateral accretion coexisting with deeper water or marine deposit, which is an organically consecutive en bloc, in harmony with Walther's law of facies, principle of paleoecology, in harmony with coal seam thickness, changeable configuration, many and varied underlying sedimentary systems, also in harmony with coalforming material super huge industrial enrichment, coal-bearing strata gray, grayish black in color and coal deposit high quality facts.%煤层成因是煤地质学的核心.煤层是一种沉积地层,它遵循沉积学、地层学、岩石学以及矿床学的基本规律,也有其特殊性,其成因并不同于煤的成因.传统煤地质学的核心观点是煤层由泥炭沼泽演化而成,其本质就是成煤物质的

  3. Facies conditions of the 2. Lusatian seam horizon in the area East of Peitz

    Energy Technology Data Exchange (ETDEWEB)

    Boenisch, R.; Liskow, C.

    1988-07-01

    Characterizes the Miocene brown coal deposit in the area Peitz, Jaenschwalde and Guben (GDR) by methods of paleobotany and paleogeography. Results of macropetrographic facies analysis and geophysical borehole measurements were employed in the study. Geologic profiles of the region as well as maps of seam distribution were drawn up. The analysis proves that prehistoric river meanders divide the brown coal moor into a northern and a southern section. A description of the paleoenvironment and the sedimentation process is given. A correlation between coal facies and technological coal quality is pointed out. The study is being used to develop a geologic seam model for this brown coal mining area. 9 refs.

  4. Forward Modeling of the Relationship Between Reflection Coefficient and Incident Angle of the P Wave in a Coal Seam

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Although the Zoeppritz equation is suitable for a single interface in a thick deposit, it has some limitations for composite reflection waves from both the floor and the roof of coal seams. Based on the ray model, the relationship of the overall reflection coefficient of composite reflection P waves, from coal seam versus incidence angle (AVO), is discussed. The result shows that: 1) the overall reflection coefficient of composite reflection waves from coal seams is a negative value and is determined mainly by the lithology of roof and floor, which is different from the reflection coefficient of a single interface; 2) if the incidence angle ranges from 0° to 6°, the reflection coefficient of composite waves of a coal seam does not change with the incidence angle and 3) if the incidence angle ranges from 6-60° , the reflection coefficient increases monotonically.

  5. Technique of coal mining and gas extraction without coal pillar in multi-seam with low permeability

    Institute of Scientific and Technical Information of China (English)

    YUAN Liang

    2009-01-01

    Aimed at the low mining efficiency in deep multi-seams because of high crustal stress, high gas content, low permeability, the compound "three soft" roof and the trouble-some safety situation encountered in deep level coal exploitation, proposed a new idea of gob-side retaining without a coal-pillar and Y-style ventilation in the first-mined key pres-sure-relieved coal seam and a new method of coal mining and gas extraction. The follow-ing were discovered: the dynamic evolution law of the crannies in the roof is influenced by mining, the formative rule of "the vertical cranny-abundant area" along the gob-side, the distribution of air pressure field in the gob, and the flowing rule of pressure-relieved gas in a Y-style ventilation system. The study also established a theoretic basis for a new mining method of coal mining and gas extraction which is used to extract the pressure-relieved gas by roadway retaining boreholes instead of roadway boreholes. Studied and resolved many difficult key problems, such as, fast roadway retaining at the gob-side without a coal-pillar, Y-style ventilation and extraction of pressure-relieved gas by roadway retaining boreholes, and so on. The study innovated and integrated a whole set of technical sys-tems for coal and pressure relief gas extraction. The method of the pressure-relieved gas extraction by roadway retaining had been successfully applied in 6 typical working faces in the Huainan and Huaibei mining areas. The research can provide a scientific and reliable technical support and a demonstration for coal mining and gas extraction in gaseous deep multi-seams with low permeability.

  6. Numerical simulation of influence of Langmuir adsorption constant on gas drainage radius of drilling in coal seam

    Institute of Scientific and Technical Information of China (English)

    Lin Haifei; Huang Meng; Li Shugang; Zhang Chao; Cheng Lianhua

    2016-01-01

    To determine reasonable distance of gas pre-drainage drillings in coal seams, a solid–gas coupling model that takes gas adsorption effect into account was constructed. In view of different adsorption constants, the paper conducted the numerical simulation of pre-drainage gas in drillings along coal seam, studied the relationship of adsorption constants and permeability, gas pressure, and effective drainage radius of coal seams, and applied the approach to the layout of pre-drainage gas drillings in coal seams. The results show that the permeability of coal seams is on the gradual increase with time, which is divided into three sections according to the increase rate:the drainage time 0–30 d is the sharp increase section;30–220 d is the gradual increase section;and the time above 200 d is the stable section. The permeability of coal seams is in negative linear and positive exponent relation with volume adsorption constant VL and pressure adsorption constant PL, respectively. The effective drainage radius is in negative linear relation with VL and in positive exponent relation with PL. Compared with the former design scheme, the engi-neering quantity of drilling could be reduced by 25%.

  7. Organic geochemical study of sequences overlying coal seams; example from the Mansfield Formation (Lower Pennsylvanian), Indiana

    Science.gov (United States)

    Mastalerz, Maria; Stankiewicz, A.B.; Salmon, G.; Kvale, E.P.; Millard, C.L.

    1997-01-01

    Roof successions above two coal seams from the Mansfield Formation (Lower Pennsylvanian) in the Indiana portion of the Illinois Basin have been studied with regard to sedimentary structures, organic petrology and organic geochemistry. The succession above the Blue Creek Member of the Mansfield Formation is typical of the lithologies covering low-sulphur coals ( 2.%). The transgressive-regressive packages above both seams reflect the periodic inundation of coastal mires by tidal flats and creeks as inferred from bioturbation and sedimentary structures such as tidal rhythmites and clay-draped ripple bedforms. Geochemistry and petrology of organic facies above the Blue Creek coal suggest that tidal flats formed inland in fresh-water environments. These overlying fresh water sediments prevented saline waters from invading the peat, contributing to low-sulphur content in the coal. Above the unnamed coal, trace fossils and geochemical and petrological characteristics of organic facies suggest more unrestricted seaward depositional environment. The absence of saline or typically marine biomarkers above this coal is interpreted as evidence of very short periods of marine transgression, as there was not enough time for establishment of the precursor organisms for marine biomarkers. However, sufficient time passed to raise SO42- concentration in pore waters, resulting in the formation of authigenic pyrite and sulphur incorporation into organic matter.

  8. Prediction and control of rock burst of coal seam contacting gas in deep mining

    Institute of Scientific and Technical Information of China (English)

    WANG En-yuan; LIU Xiao-fei; ZHAO En-lai; LIU Zhen-tang

    2009-01-01

    By analyzing the characteristics and the production mechanism of rock burst that goes with abnormal gas emission in deep coal seams, the essential method of elimi-nating abnormal gas emission by eliminating the occurrence of rock burst or depressing the magnitude of rock burst was considered. The No.237 working face was selected as the typical working face contacting gas in deep mining; aimed at this working face, a sys-tem of rock burst prediction and control for coal seam contacting gas in deep mining was established. This system includes three parts: ① regional prediction of rock burst hazard before mining, ② local prediction of rock burst hazard during mining, and ③ rock burst control.

  9. Study on the countermeasures against methane outburst of mining multiple upper protective layers in coal seams cluster

    Institute of Scientific and Technical Information of China (English)

    XIE Guang-xiang; LUO Yong

    2005-01-01

    In order to prevent coal and methane outbursts, mining protective layers is an effective means, yet no precedents of mining multiple protective layers is discoveried in seams which includes several seams are prone to outburst like Xinzhuangzi Mine. This paper perfected the related theories through analyzing mining multiple upper protective layers. By means of examining several parameters, it synthetically analyzed and ascertains the protected effectiveness and scope and reasonable parameters, finally obtained the specific indexes and effectiveness of mining multiple protective layers in coal seams cluster.

  10. Technique of coal mining and gas extraction without coal pillar in multi-seam with low permeability

    Energy Technology Data Exchange (ETDEWEB)

    Liang Yuan [Huainan Mining (Group) Co. Ltd., Huainan (China)

    2009-06-15

    Aimed at the low mining efficiency in deep multi-seams because of high crustal stress, high gas content, low permeability, the compound 'three soft' roof and the troublesome safety situation encountered in deep level coal exploitation, a new idea of gob-side retaining without a coal-pillar and Y-style ventilation in the first-mined key pressure-relieved coal seam and a new method of coal mining and gas extraction was proposed. The following were discovered: the dynamic evolution law of the crannies in the roof is influenced by mining, the formative rule of 'the vertical cranny-abundant area' along the gob-side, the distribution of air pressure field in the gob, and the flowing rule of pressure-relieved gas in a Y-style ventilation system. The study also established a theoretic basis for a new mining method of coal mining and gas extraction which is used to extract the pressure-relieved gas by roadway retaining boreholes instead of roadway boreholes. Studied and resolved many difficult key problems, such as, fast roadway retaining at the gob-side without a coalpillar, Y-style ventilation and extraction of pressure-relieved gas by roadway retaining boreholes, and so on. The study innovated and integrated a whole set of technical systems for coal and pressure relief gas extraction. The method of the pressure-relieved gas extraction by roadway retaining had been successfully applied in 6 typical working faces in the Huainan and Huaibei mining areas. The research can provide a scientific and reliable technical support and a demonstration for coal mining and gas extraction in gaseous deep multi-seams with low permeability. 9 refs., 7 figs.

  11. Key technologies and equipment for a fully mechanized top-coal caving operation with a large mining height at ultra-thick coal seams

    Institute of Scientific and Technical Information of China (English)

    Jinhua Wang; Bin Yu; Hongpu Kang; Guofa Wang; Debing Mao; Yuntao Liang; Pengfei Jiang

    2015-01-01

    Thick and ultra-thick coal seams are main coal seams for high production rate and high efficiency in Chinese coal mines, which accounts for 44%of the total minable coal reserve. A fully mechanized top-coal caving mining method is a main underground coal extraction method for ultra-thick coal seams. The coal extraction technologies for coal seams less than 14 m thick were extensively used in China. However, for coal seams with thickness greater than 14 m, there have been no reported cases in the world for underground mechanical extraction with safe performance, high efficiency and high coal recovery ratio. To deal with this case, China Coal Technology&Engineering Group, Datong Coal Mine Group, and other 15 organizations in China launched a fundamental and big project to develop coal mining technologies and equipment for coal seams with thicknesses greater than 14 m. After the completion of the project, a coal extraction method was developed for top-coal caving with a large mining height, as well as a ground control theory for ultra-thick coal seams. In addition, the mining technology for top-coal caving with a large mining height, the ground support technology for roadway in coal seams with a large cross-section, and the prevention and control technology for gas and fire hazards were developed and applied. Furthermore, a hydraulic support with a mining height of 5.2 m, a shearer with high reliability, and auxiliary equipment were developed and manufactured. Practical implication on the technologies and equipment developed was successfully completed at the No. 8105 coal face in the Tashan coal mine, Datong, China. The major achievements of the project are summarized as follows:1. A top-coal caving method for ultra-thick coal seams is proposed with a cutting height of 5 m and a top-coal caving height of 15 m. A structural mechanical model of overlying strata called cantilever beam-articulated rock beam is established. Based on the model, the load resistance of the

  12. A new numerical approach of coupled modeling for solid deformation and gas leak flow in multi-coal-seams

    Institute of Scientific and Technical Information of China (English)

    SUN Pei-de; GUO Mao-xin

    2005-01-01

    From the viewpoint of interaction mechanics for solid and gas, a coupled mathematical model was presented for solid coal/rock deformation and gas leak flow in parallel deformable coal seams. Numerical solutions using the SIP (Strong Implicit Procedure) method to the coupled mathematical model for double parallel coal seams were also developed in detail. Numerical simulations for the prediction of the safety range using protection layer mining were performed with experimental data from a mine with potential danger of coal/gas outbursts. Analyses show that the numerical simulation results are consistent with the measured data in situ.

  13. Method for stabilizing quality of coal extracted from seams with a complicated structure

    Energy Technology Data Exchange (ETDEWEB)

    Belyakov, Yu.I.; Pushkin, S.P. (Kievskii Inzhenerno-Stroitel' nyi Institut (Ukraine))

    1992-02-01

    Discusses methods for stabilizing coal quality (ash content) under conditions of complicated coal deposit structure (coal seams separated by thin rock layers). Computerized simulation of operation of a set of equipment for coal surface mining and mine haulage (bucket wheel excavators, locomotives and mine cars) is discussed. Output of individual excavators, ash content in coal from the face mined by each excavator and effects of coal mixing during haulage and handling on fluctuations of ash content in run-of-mine coal are analyzed. Computerized simulation shows that under conditions of the Ehkibastuz an optimum system for coal mixing and haulage should consist of bucket wheel excavators with output reserves ranging from 10 to 20% and haulage systems with 4 to 5 reserve train routes to coal yards. Such a system guarantees a reduction of ash content (mean square deviation) by 30-35%, reduction of idle time of mine cars by 35-40% and reduction of coal mining cost by 4-6%. 3 refs.

  14. Annual Change Detection by ASTER TIR Data and an Estimation of the Annual Coal Loss and CO2 Emission from Coal Seams Spontaneous Combustion

    Directory of Open Access Journals (Sweden)

    Xiaomin Du

    2014-12-01

    Full Text Available Coal fires, including both underground and coal waste pile fires, result in large losses of coal resources and emit considerable amounts of greenhouse gases. To estimate the annual intensity of greenhouse gas emissions and the loss of coal resources, estimating the annual loss from fire-influenced coal seams is a feasible approach. This study assumes that the primary cause of coal volume loss is subsurface coal seam fires. The main calculation process is divided into three modules: (1 Coal fire quantity calculations, which use change detection to determine the areas of the different coal fire stages (increase/growth, maintenance/stability and decrease/shrinkage. During every change detections, the amount of coal influenced by fires for these three stages was calculated by multiplying the coal mining residual rate, combustion efficiency, average thickness and average coal intensity. (2 The life cycle estimate is based on remote sensing long-term coal fires monitoring. The life cycles for the three coal fire stages and the corresponding life cycle proportions were calculated; (3 The diurnal burnt rates for different coal fire stages were calculated using the CO2 emission rates from spontaneous combustion experiments, the coal fire life cycle, life cycle proportions. Then, using the fire-influenced quantity aggregated across the different stages, the diurnal burn rates for the different stages and the time spans between the multi-temporal image pairs used for change detection, we estimated the annual coal loss to be 44.3 × 103 tons. After correction using a CH4 emission factor, the CO2 equivalent emissions resulting from these fires was on the order of 92.7 × 103 tons. We also discovered that the centers of these coal fires migrated from deeper to shallower parts of the coal seams or traveled in the direction of the coal seam strike. This trend also agrees with the cause of the majority coal fires: spontaneous combustion of coalmine goafs.

  15. Influence of Lithological Characters of Coal Bearing Formation on Stability of Roof of Coal Seams

    Institute of Scientific and Technical Information of China (English)

    孟召平; 彭苏萍; 李国庆; 黄为; 芦俊; 雷志勇

    2003-01-01

    Lithology is one of the important factors influencing the stability of roof of coal seams. In order to investigate this, the phenomenon of underground pressure and distribution of pressure were studied by using the local observation and simulation test with similar materials. The observation results show that the distance of initial weighting and periodic weighting of the mudstone roof is shorter than that of sandstone roofs. The sandstone roof with a high strength has a longer distance of initial weighting and periodic weighting, the abutment stress on the working face is big and the height of caving and fracture zone is high. The peak point of abutment stress in the sandstone roof is near to the working face and the pressure bump is inclined to occur. The result is contrary to that in case of the mudstone roof with a low strength. While in the transition zone of nipped sandstone, roof rock-mass is broken and is poor in stability, therefore, it is difficult to hold the roof.

  16. Estimation of Coal Bed Methane Potential of Coal Seams of Margherita Coal Field, Assam, India

    Directory of Open Access Journals (Sweden)

    Prasenjit Talukdar

    2015-06-01

    Full Text Available The rapid industrialization and growing energy needs have put a great stress on the conventional energy resources. This is even more concerning for a country like India which is a net importer of oil. To meet the ever increasing need for energy, it is essential that the search for unconventional energy is intensified. This paper deals with the estimation of coal bed methane potential of the Margherita Coal Field of Assam, India. For this purpose, eight coal samples were collected from Tirap O.C.P., Ledo UG Incline and Tikak O.C.P collieries of the Margherita coal field. Proximate analysis, megascopic study and finally qualitative analysis of these eight samples was undertaken. After analysis, the inferred reserves of CBM at Margherita Coalfield, was found to be in the range of 42.5-49.04 Billion Cubic Meter.

  17. Numerical Study on 4-1 Coal Seam of Xiaoming Mine in Ascending Mining

    Directory of Open Access Journals (Sweden)

    Lan Tianwei

    2015-01-01

    Full Text Available Coal seams ascending mining technology is very significant, since it influences the safety production and the liberation of dull coal, speeds up the construction of energy, improves the stability of stope, and reduces or avoids deep hard rock mining induced mine disaster. Combined with the Xiaoming ascending mining mine 4-1, by numerical calculation, the paper analyses ascending mining 4-1 factors, determines the feasibility of ascending mining 4-1 coalbed, and proposes roadway layout program about working face, which has broad economic and social benefits.

  18. Numerical study on 4-1 coal seam of Xiaoming mine in ascending mining.

    Science.gov (United States)

    Lan, Tianwei; Zhang, Hongwei; Li, Sheng; Han, Jun; Song, Weihua; Batugin, A C; Tang, Guoshui

    2015-01-01

    Coal seams ascending mining technology is very significant, since it influences the safety production and the liberation of dull coal, speeds up the construction of energy, improves the stability of stope, and reduces or avoids deep hard rock mining induced mine disaster. Combined with the Xiaoming ascending mining mine 4-1, by numerical calculation, the paper analyses ascending mining 4-1 factors, determines the feasibility of ascending mining 4-1 coalbed, and proposes roadway layout program about working face, which has broad economic and social benefits.

  19. Hybrid Technology of Hard Coal Mining from Seams Located at Great Depths

    Science.gov (United States)

    Czaja, Piotr; Kamiński, Paweł; Klich, Jerzy; Tajduś, Antoni

    2014-10-01

    Learning to control fire changed the life of man considerably. Learning to convert the energy derived from combustion of coal or hydrocarbons into another type of energy, such as steam pressure or electricity, has put him on the path of scientific and technological revolution, stimulating dynamic development. Since the dawn of time, fossil fuels have been serving as the mankind's natural reservoir of energy in an increasingly great capacity. A completely incomprehensible refusal to use fossil fuels causes some local populations, who do not possess a comprehensive knowledge of the subject, to protest and even generate social conflicts as an expression of their dislike for the extraction of minerals. Our times are marked by the search for more efficient ways of utilizing fossil fuels by introducing non-conventional technologies of exploiting conventional energy sources. During apartheid, South Africa demonstrated that cheap coal can easily satisfy total demand for liquid and gaseous fuels. In consideration of current high prices of hydrocarbon media (oil and gas), gasification or liquefaction of coal seems to be the innovative technology convergent with contemporary expectations of both energy producers as well as environmentalists. Known mainly from literature reports, underground coal gasification technologies can be brought down to two basic methods: - shaftless method - drilling, in which the gasified seam is uncovered using boreholes drilled from the surface, - shaft method, in which the existing infrastructure of underground mines is used to uncover the seams. This paper presents a hybrid shaft-drilling approach to the acquisition of primary energy carriers (methane and syngas) from coal seams located at great depths. A major advantage of this method is the fact that the use of conventional coal mining technology requires the seams located at great depths to be placed on the off-balance sheet, while the hybrid method of underground gasification enables them to

  20. Effect of the computer fuzzy control on coal seam injection

    Institute of Scientific and Technical Information of China (English)

    SONG Hua-ling(宋华岭); YANG Jing-cai(杨景才); WANG Jin-li (王金力); WANG An(王安); LIU Shu-qin(刘淑芹); Cornelis Reiman

    2003-01-01

    To enhance the technology and efficiency of strata injection is a problem to be solved urgently. Because of effected by the rough and poor production conditions of mining and the changeable bearing condition of strata, the technological process of injection can not be controlled automatically.The fuzzy controlling technology of the coal strata injection is applied. This is the good way to ensure the effectiveness and efficiency of coal strata injection and to solve the current problems of production and safety in mining industry.

  1. Pulsating hydraulic fracturing technology in low permeability coal seams

    Institute of Scientific and Technical Information of China (English)

    Wang Wenchao; Li Xianzhong; Lin Baiquan; Zhai Cheng

    2015-01-01

    Based on the difficult situation of gas drainage in a single coal bed of high gas content and low perme-ability, we investigate the technology of pulsating hydraulic pressure relief, the process of crank plunger movement and the mechanism of pulsating pressure formation using theoretical research, mathematical modeling and field testing. We analyze the effect of pulsating pressure on the formation and growth of fractures in coal by using the pulsating hydraulic theory in hydraulics. The research results show that the amplitude of fluctuating pressure tends to increase in the case where the exit is blocked, caused by pulsating pressure reflection and frictional resistance superposition, and it contributes to the growth of fractures in coal. The crack initiation pressure of pulsating hydraulic fracturing is 8 MPa, which is half than that of normal hydraulic fracturing;the pulsating hydraulic fracturing influence radius reaches 8 m. The total amount of gas extraction is increased by 3.6 times, and reaches 50 L/min at the highest point. The extraction flow increases greatly, and is 4 times larger than that of drilling without fracturing and 1.2 times larger than that of normal hydraulic fracturing. The technology provides a technical measure for gas drainage of high gas content and low permeability in the single coal bed.

  2. Research into comprehensive gas extraction technology of single coal seams with low permeability in the Jiaozuo coal mining area

    Institute of Scientific and Technical Information of China (English)

    Fu Jiangwei; Fu Xuehai; Hu Xiao; Chen Li; Ou Jianchun

    2011-01-01

    For a low permeability single coal seam prone to gas outbursts,pre-drainage of gas is difficult and inefficient,seriously restricting the safety and efficiency of production.Radical measures of increasing gas extraction efficiency are pressure relief and infrared antireflection.We have analyzed the effect of mining conditions and the regularity of mine pressure distribution in front of the working face of a major coal mine of the Jiaozuo Industrial (Group) Co.as our test area,studied the width of the depressurization zone in slice mining and analyzed gas efficiency and fast drainage in the advanced stress relaxation zone.On that basis,we further investigated and practiced the exploitation technology of shallow drilling,fan drilling and grid shape drilling at the working face.Practice and our results show that the stress relaxation zone is the ideal region for quick and efficient extraction of gas.By means of an integrated extraction technology,the amount of gas emitted into the zone was greatly reduced,while the risk of dangerous outbursts of coal and gas was lowered markedly.This exploration provides a new way to control for gas in working faces of coal mines with low permeability and risk of gas outbursts of single coal seams in the Jiaozuo mining area.

  3. Relations between coal petrology and gas content in the Upper Newlands Seam, Central Queensland, Australia

    Science.gov (United States)

    Walker, R.; Glikson, M.; Mastalerz, Maria

    2001-01-01

    The Upper Newlands Seam in the northern Bowen Basin, Queensland Australia consists of six benches (A-F) that have different petrographic assemblages. Benches C and E contain relatively abundant inertodetrinite and mineral matter, as well as anomalously high reflectance values; these characteristics support a largely allochthonous, detrital origin for the C and E benches. Fractures and cleats in the seam show a consistent orientation of northeast-southwest for face cleats, and a wide range of orientations for fractures. Cleat systems are well developed in bright bands, with poor continuity in the dull coal. Both maceral content and cleat character are suggested to influence gas drainage in the upper Newlands Seam. A pronounced positive correlation between vitrinite abundance and gas desorption data suggests more efficient drainage from benches with abundant vitrinite. Conversely, inertinite-rich benches are suggested to have less efficient drainage, and possibly retain gas within pore spaces, which could increase the outburst potential of the coal. ?? 2001 Elsevier Science B.V. All rights reserved.

  4. Journey to the centre of the earth: coal seam gas in Queensland

    Energy Technology Data Exchange (ETDEWEB)

    Dighton, P.

    1998-12-31

    Coal Seam Gas (CSG) is potentially an important energy source of the future. In addition to being a valuable energy source, the utilisation of CSG will also decrease significantly the adverse greenhouse effects of venting CSG to the atmosphere. Although CSG is presently being recovered and utilised in both Queensland and New South Wales, its economic viability at the moment is marginal. However technological advances or fiscal incentives could see this change rapidly. At present most of the Queensland coal fields have overlapping petroleum tenures. While this has not presented significant conflicts to date, holders of Authorities To Prospect are automatically entitled to production leases from discovery of petroleum, including coal seam gas, deposits. The Queensland government has addressed this potential conflict by producing a `final position` paper. One of the main proposals is to protect the coal mining industry by the declaration of CSG areas and strata titling of the relevant interests. The legislation, presently being drafted for submission to the new Queensland Parliament, is outlined.

  5. EVALUATION OF BROWN COAL SPONTANEOUS COMBUSTION AND SOURCES GENESIS PROGNOSES

    Directory of Open Access Journals (Sweden)

    Vlastimil MONI

    2014-10-01

    Full Text Available This article presents summarizing information about the solution of partial part of research problem of prognoses of deposited brown coal spontaneous combustion sources genesis as a part of project TA01020351 – program ALFA. We will gradually describe the results of long term measurements carried out on selected brown coal heaps realized from 2011 to 2013. The attention is devoted to characterization of key parameters. These parameters influence the genesis of combustion. The second problem is the comparison of results of thermal imaging with laboratory results of gas and coal samples sampled in situ, with the influence of atmospheric conditions (insolation, aeration, rainfall, atmospheric pressure changes etc., with influence of coal mass degradation, physical and chemical factors and another failure factors to brown coal spontaneous combustion processes.

  6. Relaxation and gas drainage boreholes for high performance longwall operations in low permeability coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Imgrund, Thomas [DMT GmbH und Co. KG, Essen (Germany); Bauer, Frank [Hazemag und EPR GmbH, Duelmen (Germany). Mining

    2013-06-15

    With an increasing depth of cover, gas emission control and gas outbursts prevention has become an increasingly important issue in coal mining. Deep multi-seam mining often requires operation in an environment characterised by a high gas content and gas pressure. Control of gas related risks has to be realised during heading and close to the longwall by proper risk assessment and flexible drilling schemes. These cover exploration and relaxation drilling, in-seam drilling for pre-drainage and cross measure drilling for drainage of roof and the floor gas emissions. DMT provides comprehensive solutions based on a scientific background. These solutions are engineered considering their technical feasibility. Hazemag Mining offers a large number of complete machinery including tools systems for the implementation of those solutions. (orig.)

  7. Explanation for peat-forming environments of coal seam 2 and 9-2 based on the maceral composition and aromatic compounds in the Xingtai coalfield, China

    Institute of Scientific and Technical Information of China (English)

    SUN Yu-zhuang; QIN Shen-jun; LI Yan-heng; LIN Ming-yue; DING Shu-li

    2009-01-01

    Maceral composition and aromatic compounds were determined on column samples to study the peat-forming environments of Permian coal seam 2 and Carbonifer-ous coal seam 9-2 from the Xingtai coalfield,China.The macerals were dominated by iner-tinite in seam 2 and by vitrinite in seam 9-2.Three maceral groups were selected as indi-cators of peat-forming environments.Two triangle diagrams were drawn based on the in-dicators to explicate the peat-forming environments of permian seam 2 and Carboniferous seam 9-2.The results indicate that the peat of carboniferous seam 9-2 formed dominantly in wet swamps,whereas the peat of Permian seam 2 formed dominantly in dry swamps and open moor environments.

  8. Forecast of Geological Gas Hazards for "Three-Soft" Coal Seams in Gliding Structural Areas

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Gas outbursts from "three-soft" coal seams (soft roof, soft floor and soft coal) constitute a very serious problem in the Ludian gliding structure area in western Henan.By means of theories and methods of gas geology, structural geology, coal petrology and rock tests, we have discussed the effect of control of several physical properties of soft roof on gas preservation and proposed a new method of forecasting gas geological hazards under open structural conditions.The result shows that the areas with type Ⅲ or Ⅳ soft roofs are the most dangerous areas where gas outburst most likely can take place.Therefore, countermeasures should be taken in these areas to prevent gas outbursts.

  9. Investigations of changes in the physical state of the formations covering coal seams with the aid of geophysical methods

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, E.; Egerszegi, P.

    1987-01-01

    Testing measurements were carried out using surface frequence probes and applying electric transillumination between various levels of two drill holes in order to observe the effect of the overburden of a face passing through the section. Having applied the apparent specific resistances determined for each depth interval, measurable changes could be observed. The greatest change occured in the surroundings of the coal seam where the resistance decreased, and in a sand layer overlying the seam where resistance increased.

  10. Research on forced gas draining from coal seams by surface well drilling

    Institute of Scientific and Technical Information of China (English)

    Wu Dongmei; Wang Haifeng; Ge Chungui; An Fenghua

    2011-01-01

    Surface drilling was performed at the Luling Coal Mine, in Huaibei, to shorten the period required for gas draining. The experimental study was designed to reduce the cost of gas control by efficiently draining gas from the upper protected layer. The structural arraignment and technical principles of pressure relief via surface drilling are discussed. Results from the trial showed that gas drained from the surface system over a period of 10 months. The total amount of collected gas was 248.4 million m3. The gas draining occurred in three stages: a growth period; a period of maximum gas production; and an attenuation period. The period of maximum gas production lasted for 4 months. During this time the methane concentration ranged from 60% to 90% and the average draining rate was 10.6 m3/min. Combined with other methods of draining it was possible to drain 70.6% of the gas from middle coal seam groups. The amount of residual gas dropped to 5.2 m3/ton, and the pressure of the residual gas fell to 0.53 MPa,thereby eliminating the outburst danger in the middle coal seam groups. The factors affecting pressure relief gas draining by surface drilling were analysed.

  11. Auxiliary transportation mode in a fully-mechanized face in a nearly horizontal thin coal seam

    Institute of Scientific and Technical Information of China (English)

    Wang Chen; Tu Shihao; Zhang Lei; Yang Qianlong; Tu Hongsheng

    2015-01-01

    On fully-mechanized faces in nearly horizontal thin coal seams (NHTCS), the selection of the auxiliary transportation mode is difficult. Generally, auxiliary transportation mainly includes trackless or rail transportation. Combined with a familiar NHTCS fully-mechanized face, a multi-attribute decision-making model was set up for the decision. The index weight was objectively determined with the fuzzy number and entropy method. The priority order of auxiliary transportation modes was obtained from the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE). The results show that: the net flow of the mode can be expressed by the function of the surrounding rock deformation of the roadway, the dimension of equipment and the thickness of the coal seam;Based on the cost type index, there is a positive correlation between the net flow with the height and width of the trackless aux-iliary transportation equipment, respectively. The trackless auxiliary transportation equipment selection principle should be‘height first then width”. Combined with the field application of the trackless auxil-iary transportation in Liangshuijing coal mine, the proper method to achieve the safe and high-efficient exploitation of a NHTCS fully-mechanized face is trackless tyred vehicle auxiliary transportation.

  12. Sequence stratigraphy, organic petrology and chemistry applied to the upper and lower coal seams in the Candiota Coalfield, Parana Basin, RS, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, J.S. de; Kalkreuth, W. [Instituto de Geociencias, UFRGS, Porto Alegre (Brazil)

    2010-12-01

    The Permian age coal seams in the Candiota Coalfield represent the largest coal deposit of the country. Currently two seams are mined, called ''Camada Candiota Superior'' and ''Camada Candiota Inferior''. The other coal seams of the coalfield, seams S1-S9 (upper seams) and I1-I5 (lower seams) have as yet not been exploited. The objective of this paper is to perform a detailed sequence stratigraphic, petrologic and chemical study of the upper and lower coal seams, thereby generating data for assisting in the development and better use of the coal-bearing interval. The methodology includes application of the concepts of sequence stratigraphy, which includes the lithological interpretation of the core to establish the depositional environments and genetic correlation between facies associations to define parasequences and bounding surfaces; coal petrology (analysis of the reflectance of vitrinite, determination of the petrographic composition of the coals by maceral analyses), and chemical analyses such as sulphur determination, proximate analyses (ash, moisture, volatile matter, and fixed carbon), and elemental analyses. Three main depositional systems were so far identified: alluvial fan, fluvial system, lagoonal estuary system. This study shows that coal development was controlled by accommodation/accumulation rates, with coal seams with greater thickness and lateral continuity being formed within the transgressive systems tract (lagoonal depositional system) of parasequence 2 (PS2), indicating that the accumulation rates of the peat and distribution of the coal seams were controlled by stratigraphic setting. Vitrinite reflectances for the upper and lower coal seams are indicative of subbituminous rank (Rrandom = 0.36-0.47%), with evidence that anomalously low reflectance values are related to high mineral-matter contents. Maceral composition is highly variable, with some coal seams being extremely rich in inertinite (up to

  13. Research on Protective Area of Exploiting Lower Protective Coal Seam and its Feasibility

    OpenAIRE

    2014-01-01

    Based on the reasonable consideration of the role of the second main stress in D-P criterion, the distribution of stress and deformation with the method of finite difference was simulated. And the stress relief angles along incline and strike according to the rules of stress and deformation were obtained. Then the protective area resulted from exploiting the lower protective coal seam were acquired. The results show that the stress relief angles along incline are 75.5 and 77.7 deg...

  14. Study on stress distribution and failure criterion of the roof for the severely inclined coal seam under long wall working

    Institute of Scientific and Technical Information of China (English)

    MENG Xiang-rui; GAO Zhao-ning; WANG Xiang-qian

    2012-01-01

    By turning to the theory of elastic thin plates,a mechanical model of the main roof breaking for severely inclined seam under long wall working was esbalished,in which formulaes were deduced for the calculation of the stress distribution.When the main roof stress distribution was characterized,the failure form of the roof in the long wall coal seam under work was given with the failure criterion deduced.The deduced failure criterion was then applied to the No.3232(3) face of the Lizuizi Coal Mine; the first pressure for the working face was accurately predicted.Results of the field application show that the main roof of the severely inclined coal seam under long wall working breaks in the O-X pattern,which is basically in accordance with the reality.

  15. Production of gas from coal seams in the Upper Silesian Coal Basin in Poland in the post-injection period of an ECBM pilot site

    NARCIS (Netherlands)

    Bergen, F. van; Krzystolik, P.; Wageningen, N. van; Pagnier, H.; Jura, B.; Skiba, J.; Winthaegen, P.; Kobiela, Z.

    2009-01-01

    A pilot site for CO2 storage in coal seams was set-up in the Upper Silesian Coal Basin in Poland in the scope of the RECOPOL project, funded by the European Commission. About 760 tons CO2 were injected into the reservoir from August 2004 to June 2005. Breakthrough of the injected CO2 was established

  16. "Knitting Nannas" and "Frackman": A Gender Analysis of Australian Anti-Coal Seam Gas Documentaries (CSG) and Implications for Environmental Adult Education

    Science.gov (United States)

    Larri, Larraine J.; Newlands, Maxine

    2017-01-01

    "Frackman" ("FM") and "Knitting Nannas" ("KN") are two documentaries about the anti-coal seam gas movement in Australia. "Frackman" features a former construction worker turned eco-activist, Dayne Pratzky (DP), fighting coal seam gas extraction. "Knitting Nannas" follows a group of women…

  17. Back-and-forth mining for hard and thick coal seams-research about the mining technology for fully mechanized caving working face of Datong Mine

    Institute of Scientific and Technical Information of China (English)

    JIN Zhi-xin; YU Hong; YU Bin; SONG Hua-ling

    2005-01-01

    The article introduced the key technology, mining process, and back-and-forth mining method for the caving working face of hard-thick coal seams in Datcng mine, and researched this innovations process, optimized the systemic design and working face outplay, tried to perfect the caving mining technology of hard-thick coal seams further.

  18. Origin of Minerals and Elements in the Late Permian Coal Seams of the Shiping Mine, Sichuan, Southwestern China

    Directory of Open Access Journals (Sweden)

    Yangbing Luo

    2016-07-01

    Full Text Available Volcanic layers in coal seams in southwestern China coalfields have received much attention given their significance in coal geology studies and their potential economic value. In this study, the mineralogical and geochemical compositions of C19 and C25 coal seams were examined, and the following findings were obtained. (1 Clay minerals in sample C19-r are argillized, and sedimentary layering is not observed. The acicular idiomorphic crystals of apatite and the phenocrysts of Ti-augite coexisting with magnetite in roof sample C19-r are common minerals in basaltic rock. The rare earth elements (REE distribution pattern of C19-r, which is characterized by positive Eu anomalies and M-REE enrichment, is the same as that of high-Ti basalt. The concentrations of Ti, V, Co, Cr, Ni, Cu, Zn, Nb, Ta, Zr, and Hf in C19-r are closer to those of high-Ti basalt. In conclusion, roof sample C19-r consists of tuffaceous clay, probably with a high-Ti mafic magma source. (2 The geochemical characteristics of the C25 coals are same as those reported for coal affected by alkali volcanic ash, enrichment in Nb, Ta, Zr, Hf, and REE, causing the C25 minable coal seams to have higher potential value. Such a vertical study of coals and host rocks could provide more information for coal-forming depositional environment analysis, for identification of volcanic eruption time and magma intrusion, and for facilitating stratigraphic subdivision and correlation.

  19. Major and Trace Element Geochemistry of Coals and Intra-Seam Claystones from the Songzao Coalfield, SW China

    Directory of Open Access Journals (Sweden)

    Lei Zhao

    2015-12-01

    Full Text Available Silicic, mafic and alkali intra-seam tonsteins have been known from SW China for a number of years. This paper reports on the geochemical compositions of coals and tonsteins from three seam sections of the Songzao Coalfield, SW China, and evaluates the geological factors responsible for the chemical characteristics of the coal seams, with emphasis on the influence from different types of volcanic ashes. The roof and floor samples of the Songzao coal seams mostly have high TiO2 contents, consistent with a high TiO2 content in the detrital sediment input from the source region, namely mafic basalts from the Kangdian Upland on the western margin of the coal basin. The coals from the Songzao Coalfield generally have high ash yields and are highly enriched in trace elements including Nb, Ta, Zr, Hf, rare earth elements (REE, Y, Hg and Se; some variation occurs among different seam sections due to input of geochemically different volcanic ash materials. The geochemistry of the Songzao coals has also been affected by the adjacent tonstein/K-bentonite bands. The relatively immobile elements that are enriched in the altered volcanic ashes also tend to be enriched in the adjacent coal plies, possibly due to leaching by groundwaters. The coals near the alkali tonstein bands in the Tonghua and Yuyang sections of the Songzao Coalfield are mostly high in Nb, Ta, Zr, Hf, Th, U, REE and Y. Coal samples overlying the mafic K-bentonite in the Tonghua section are high in V, Cr, Zn and Cu. The Datong coal, which has neither visible tonstein layers nor obvious volcanogenic minerals, has high TiO2, V, Cr, Ni, Cu and Zn concentrations in the intervals between the coal plies affected by mafic and alkaline volcanic ashes. This is consistent with the suggestion that a common source material was supplied to the coal basin, derived from the erosion of mafic basaltic rocks of the Kangdian Upland. Although the Songzao coal is generally a high-sulfur coal, most of the

  20. Geological controls on the sulphur content of coal seams in the Northumberland Coalfield, Northeast England

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Brian R. [Department of Earth Sciences, Science Laboratories, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Richardson, David [H.J. Banks and Co. Ltd, Bishop Auckland DL13 4HG (United Kingdom)

    2004-12-03

    The sulphur content of coal is an important consideration when developing reserves for exploitation, driven by emission limits from power stations becoming more stringent. Variations in the sulphur content of Westphalian A and B coals from the predominantly freshwater Northumberland Coalfield, Northeast England, were studied according to their regional, stratigraphic and in-seam location. The observed variation in sulphur content spatially increases towards the source area away from more marine influenced areas, with increased sulphur content through time linked to changes in the general depositional environment as conditions became more marine-influenced. A model of basinal surface water and groundwater flow driven by post-depositional source area tectonism is thought to have played only a minor role in contributing secondary sulphur to the coal. However, the isotopic composition of coal pyrite shows a similar range in composition to that of pyrite and other sulphides from the North Pennine Orefield along the southern margin of the coalfield, suggesting an additional potential source of secondary sulphur, as sulphur-rich fluids were expelled northwards through the coal measures during early Permian Variscan transpression from the south. The Westphalian A and B are interpreted as third-order depositional sequences, defined by third-order maximum flooding surfaces. Each sequence is made up of several coal-bearing fourth-order parasequences, which tend to be more brackish to marine in character, on either side of the third-order maximum flooding surfaces when base level was relatively high. The lowest sulphur coals are confined to the lower to middle, relative low stand part of the Westphalian A third-order base level curve and the lowest part of the Westphalian B third-order base level curve. This difference is attributed to a more rapid rise of base level in the Westphalian B. The stratigraphic and spatial distribution of coal sulphur has been used as a guide to

  1. Managing produced water from coal seam gas projects: implications for an emerging industry in Australia.

    Science.gov (United States)

    Davies, Peter J; Gore, Damian B; Khan, Stuart J

    2015-07-01

    This paper reviews the environmental problems, impacts and risks associated with the generation and disposal of produced water by the emerging coal seam gas (CSG) industry and how it may be relevant to Australia and similar physical settings. With only limited independent research on the potential environmental impacts of produced water, is it necessary for industry and government policy makers and regulators to draw upon the experiences of related endeavours such as mining and groundwater extraction accepting that the conclusions may not always be directly transferrable. CSG is widely touted in Australia as having the potential to provide significant economic and energy security benefits, yet the environmental and health policies and the planning and regulatory setting are yet to mature and are continuing to evolve amidst ongoing social and environmental concerns and political indecision. In this review, produced water has been defined as water that is brought to the land surface during the process of recovering methane gas from coal seams and includes water sourced from CSG wells as well as flowback water associated with drilling, hydraulic fracturing and gas extraction. A brief overview of produced water generation, its characteristics and environmental issues is provided. A review of past lessons and identification of potential risks, including disposal options, is included to assist in planning and management of this industry.

  2. Recycling of coal seam gas-associated water using vacuum membrane distillation.

    Science.gov (United States)

    Heidarpour, Farideh; Shi, Jeffrey; Chae, So-Ryong

    2015-01-01

    Coal seam gas-associated water (CSGAW), which is a by-product of coal seam gas (CSG) production typically contains significant amounts of salts and has potential environmental issues. In this study, we optimized a bench-scale vacuum membrane distillation (VMD) process with flat-sheet hydrophobic polytetrafluoroethylene (PTFE) membranes for the treatment of synthetic CSGAW (conductivity = 15 mS/cm). To study performance of the VMD process, we explored the effects of feed temperature (T(f) = 60, 70, and 80°C), feed flow rate (V(f) = 60, 120, and 240 mL/min), and vacuum pressure (P(v) = 3, 6, and 9 kPa) on water permeability through the PTFE membrane in the VMD process. Under the optimum conditions (i.e. T(f) = 80°C, V(f) = 240 mL/min, P(v) = 3 kPa), water permeability and rejection efficiency of salts by the VMD process were found to be 5.5 L/m(2)/h (LMH) and 99.9%, respectively, after 2 h filtration. However, after 8 h operation, the water permeability decreased by 70% compared with the initial flux due to the formation of fouling layer of calcium, chloride, sodium, magnesium, and potassium on the membrane surface.

  3. A case study of multi-seam coal mine entry stability analysis with strength reduction method

    Institute of Scientific and Technical Information of China (English)

    Tulu Ihsan Berk; Esterhuizen Gabriel S.; Klemetti Ted; Murphy Michael M.; Sumner James; Sloan Michael

    2016-01-01

    In this paper, the advantage of using numerical models with the strength reduction method (SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated. A coal mine under vari-able topography from the Central Appalachian region is used as a case study. At this mine, unexpected roof conditions were encountered during development below previously mined panels. Stress mapping and observation of ground conditions were used to quantify the success of entry support systems in three room-and-pillar panels. Numerical model analyses were initially conducted to estimate the stresses induced by the multiple-seam mining at the locations of the affected entries. The SRM was used to quan-tify the stability factor of the supported roof of the entries at selected locations. The SRM-calculated sta-bility factors were compared with observations made during the site visits, and the results demonstrate that the SRM adequately identifies the unexpected roof conditions in this complex case. It is concluded that the SRM can be used to effectively evaluate the likely success of roof supports and the stability condition of entries in coal mines.

  4. Current status and technical challenges of CO2 storage in coal seams and enhanced coalbed methane recovery:an overview

    Institute of Scientific and Technical Information of China (English)

    Xiaochun Li; Zhi-ming Fang

    2014-01-01

    In the past two decades, research on CO2 storage in coal seams and simultaneously enhanced coalbed methane recovery (ECBM) has attracted a lot of attention due to its win–win effect between greenhouse gas (CO2) emission reduction and coalbed methane recovery enhancement. This paper presents an overview on the current status of research on CO2-ECBM in the past two decades, which involves CO2 storage capacity evaluations, laboratory investigations, mod-elings and pilot tests. The current status shows that we have made great progress in the ECBM technology study, especially in the understanding of the ECBM mechanisms. However, there still have many technical challenges, such as the definition of unmineable coal seams for CO2 storage capacity evaluation and storage site characterization, methods for CO2 injec-tivity enhancement, etc. The low injectivity of coal seams and injectivity loss with CO2 injection are the major technique challenges of ECBM. We also search several ways to promote the advancement of ECBM technology in the present stage, such as integrating ECBM with hydraulic fracturing, using a gas mixture instead of pure CO2 for injection into coal seams and the application of ECBM to underground coal mines.

  5. Underground pressure appearance laws analysis for fully mechanized top coal slice caving on high-dipping thick coal seams

    Institute of Scientific and Technical Information of China (English)

    YANG Sheng-li; CAO Guang-ming; LI Fu-sheng

    2011-01-01

    Taking Adaohai Coal Mine as the example, underground pressure appearance laws of fully mechanized top coal slice caving on high-dipping and thick coal seams. Through site visit, theoretical analysis and discrete element calculation, the research shows that, as the mining deepens, underground stress of lower sublevels is more obvious and higher than that of upper sublevels and is higher in the air return roadway than that in the air intake roadway in the area that is near to the top coal.Because the top coal is thick and gangue is caved above the support, underground pressure to the working face is relatively gentle. Immediate roof will mainly fall down along the floor. Main roof and the rock bed above the main roof will move to the mined out area along the fault in the early stage and then fall down with the mined out area later. In addition, roof pressure mainly periodically appears in two directions along the trend and the dip.

  6. Forecasting the degree of rock burst hazard in areas of gas bearing coal seams by the electromagnetic radiation method

    Energy Technology Data Exchange (ETDEWEB)

    Proskuryakov, V.M.; Shabarov, A.N.; Frid, V.I. (Vsesoyuznyi Nauchno-Issledovatel' skii Institut Gornoi Geomekhaniki i Marksheiderskogo Dela (USSR))

    1991-02-01

    Presents results of investigations into emission of electromagnetic waves in zones of increased rock burst hazard conducted during drivage of a ventilation gallery in the Anzherskaya mine (Severokuzbassugol' association). Relationships between the emission of electromagnetic impulses, yield of drilling, gas yield rate, the distance between increased stress zones and seam denudation and time are discussed and presented in diagrams. Regularities of variation in electromagnetic radiation at various stress states in coal seam boundary parts with the gas yield factor taken into account were found. Suitability of recording electromagnetic radiation for forecasting rock burst hazards was shown and criteria for evaluating the degree of rock burst hazard for a coal seam in the Anzherskaya mine are presented. 3 refs.

  7. ECONOMIC EFFICIENCY IN USAGE OF BELARUSIAN BROWN COAL DEPOSITS

    Directory of Open Access Journals (Sweden)

    V. V. Kravchenko

    2011-01-01

    Full Text Available Methodology for economic evaluation of the effective use of the Belarusian brown coal deposits has been developed on the basis of systematic analysis of scientific, statistical and economic data. The obtained methodology allows to perform multi-variant optimization calculations under various uncertainty level without reduction to the same energy effect that is especially important while developing economic forecasts and programs for the long term perspective. Using this methodology evaluation of various directions pertaining to usage of the Belarusian brown coal has been done and recommendations on their possible application have been given in the paper.

  8. Fracture evolution and pressure relief gas drainage from distant protected coal seams under an extremely thick key stratum

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; CHENG Yuan-ping; LI Feng-rong; WANG Hai-feng; LIU Hai-bo

    2008-01-01

    When an extremely thick rock bed exists above a protected coal seam in the bending zone given the condition of a mining protective seam, this extremely thick rock bed controls the movement of the entire overlying stratum. This extremely thick rock bed, called a "main key stratum", will not subside nor break for a long time, causing lower fractures and bed separations not to close and gas can migrate to the bed separation areas along the fractures. These bed separations become gas enrichment areas. By analyzing the rule of fracture evolution and gas migration under the main key stratum after the deep protective coal seam has been mined, we propose a new gas drainage method which uses bore holes, drilled through rock and coal seams at great depths for draining pressure relief gas. In this method, the bores are located at a high level suction roadway (we can also drill them in the drilling field located high in an air gateway). Given the practice in the Halzi mine, the gas drainage rate can reach 73% in the middie coal group, with a gas drainage radius over 100 m.

  9. Modeling of air-gas and dynamic processes in driving development workings in the gas-bearing coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Presler, V.T. [Russian Academy of Science, Kemerovo (Russian Federation). Siberian Branch, Inst. of Coal & Coal Fuel Chemistry

    2002-04-01

    The models for air-gas processes of different hierarchical level are considered in designing and driving development workings in the coal seams. The procedure is proposed for model adaptation according to the on-line data, which makes it possible to estimate the state of medium and working capacity of measuring equipment.

  10. Matter Composition and Two Stage Evolution of a Liangshan Super High-Sulfur Coal Seam in Kaili, Eastern Guizhou

    Institute of Scientific and Technical Information of China (English)

    YI Tong-sheng; QIN Yong; ZHANG Jing; WU Yan-yan; LI Zhuang-fu

    2007-01-01

    Super-high sulfur coal resultes in serious coal-derived pollution but might have a particular genesis. Thus, a columnar section of an Early Permian Liangshan Formation coal seam. weight average sulfur content 5.80%, from Kaili, eastern Guizhou, was studied using the methods of coal petrology and geochemistry. The results show that the seam was apparently formed in seawater-effected peat bogs that developed in two distinct stages. During the first stage various layers were formed in a supratidal bog and have a composition characteristic of a bog with a gradually decreasing seawater effect, decreasing water dynamics, and an increasingly reductive environment. Layers in the upper seam formed during a second stage in an intertidal bog. These layers are very high in total and inorganic sulfur, the ratios of organic/inorganic sulfur and V/I drop, they are high in coal ash yield and have a high ash component index, considerable barkinite, oxidized and detrital macerals, have a porphyroclatic micro-structure and are rich in pyrite, all of which indicate the coal-forming environment had higher oxidation potential, strong and roiling water dynamics, and intermittent exposure to a sulfur rich environment.

  11. CO2 sequestration in deep coal seams: experimental characterization of the fundamental underlying mechanisms

    Science.gov (United States)

    Pini, R.; Mazzotti, M.

    2012-04-01

    The process of injecting and storing carbon dioxide (CO2) into suitable deep geological formations, such as saline aquifers, (depleted) oil or gas reservoirs, and unmineable coal seams, is referred to as CO2 sequestration. In little more than a decade, this technology has emerged as one of the most important options for reducing CO2 emissions. Among the different options, unmineable coal seams are not as broadly distributed as saline aquifers or oil/gas reservoirs, but their peculiarity resides in the proven capacity of retaining significant amount of gas (mainly methane, CH4) for a very long time. Additionally, the injection of CO2 into the coal reservoir would enhance the recovery of this natural gas, a source of energy that will most likely play a key role in the power sector over the next 20 years from now. This process is called Enhanced Coal Bed Methane (ECBM) recovery and, as for enhanced oil recovery, it allows in principle offsetting the costs associated to the storage operation. A study was undertaken aimed at the experimental characterization of the fundamental mechanisms that take place during the process of injection and storage in coal reservoirs, namely adsorption and swelling (Pini et al 2010), and of their effects on the coal's permeability (Pini et al. 2009), the property that plays a dominant role in controlling fluid transport in a porous rock. An apparatus has been built that allows measuring the permeability of rock cores under typical reservoir conditions (high pressure and temperature) by the so-called transient step method. For this study, a coal core from the Sulcis coal mine in Sardinia (Italy) has been used. In the experiments, an inert gas (helium) was used to investigate the effects of the effective pressure on the permeability of the coal sample, whereas two adsorbing gases (CO2 and N2) to quantify those of adsorption and swelling. The experiments have been interpreted by a one-dimensional model that describes the fluid transport

  12. Huge thick conglomerate movement induced by full thick longwall mining huge thick coal seam

    Institute of Scientific and Technical Information of China (English)

    Ma Liqiang; Qiu Xiaoxiang; Dong Tao; Zhang Jixiong; Huang Yanli

    2012-01-01

    A discrete elemental method was used to study the thickness of conglomerate layer in a full thick seam mining activities under the influence of the law,pointing out the thickness of the conglomerate at different seam mining,and during the destruction and instability of existing state of laws.At 21141 thick seam mining,the face toward the direction of separation between the thick layer of conglomerate rock and the next bit after reaching its maximum capacity due to pull from the bottom of the plastic zone,formed a stratified and hierarchical down collapse.The shape of caving area is a "triangular block",the length of the plastic zone and face advancement from the linear fit between the height of the plastic zone and the advancing face is a quadratic function of distance,while the top layer of thick gravel layer is the overall bending subsidence trend.Tilting the direction of the face,a thick gob of collapsed conglomerate layer is formed in the coal gob entity on both sides of the thick conglomerate at the top of the overall fracture morphology performance,thus forming a mutual extrusion of articulated block structure.The instability,separation and balance of the thick conglomerate layer in the hinged block stope stress leads to abnormal occurrence of rock burst induced by face as the major factor in the accident.This research reveals the form of stress distribution in the destroyed layer of the thick conglomerate rock,analyzes the stope law of coupling for the pressure burst behavior law for the mining work face,and the choice of preventive measures to provide a theoretical basis and implementation.

  13. Investigations of safety measures against rock bursts in Stara Jama of the brown coal mine 'Zenica'

    Energy Technology Data Exchange (ETDEWEB)

    Osmanagic, M.; Kocar, F.; Petkovic, L.; Teskeredzic, S.

    1979-01-01

    This paper provides a detailed historical review, with charts, illustrations and formulae used, of the cause, effect, research done, and safety measures taken concerning rock bursts in the Stara Jama seam of the Zenica brown coal mine in Yugoslavia. The geological conditions of the seam, with high calorific value and strength lying in very hard and elastic limestone and limestone marls, are reviewed. From 1962 onward, systematic recording and classification of rock burst frequency, size, intensity, and location have been carried out. Some observations are: regular mining of the relaxed overlaying seam without leaving pillars proved effective relative to reducing rock burst danger; rate of advance considerably affects the number and intensity of rock bursts; breaking of the basic hanging wall is an important factor; coal pillars between two goafs is dangerous for mining. Partial success has been achieved in forecasting and artificially provoking rock bursts. Stress relaxation by blasting has proved to be the most effective measure. Advances have also been made in reducing stored energy by water injection under high pressure. (14 refs.) (In English)

  14. Nonlinear coupling analysis of coal seam floor during mining based on FLAC3D

    Institute of Scientific and Technical Information of China (English)

    YAO Duo-xi; XU Ji-ying; LU Hai-feng

    2011-01-01

    Based on the hydro-geological conditions of 1028 mining face in Suntuan Coal Mine, mining seepage strain mechanism of seam floor was simulated by a nonlinear coupling method, which applied fluid-solid coupling analysis module of FLAC3D. The results indicate that the permeability coefficient of adjoining rock changes a lot due to mining. The maximum value reaches 1 379.9 times to the original value, where it is at immediate roof of the mined-out area. According to the analysis on the seepage field, mining does not destroy water resistance of the floor aquiclude. The mining fissure does not conduct lime-stone aquifer, and it is less likely to form damage. The plastic zone does not exactly correspond to the seepage area, and the scope of the altered seepage area is much larger than the plastic zone.

  15. Coal seam gas water: potential hazards and exposure pathways in Queensland.

    Science.gov (United States)

    Navi, Maryam; Skelly, Chris; Taulis, Mauricio; Nasiri, Shahram

    2015-01-01

    The extraction of coal seam gas (CSG) produces large volumes of potentially contaminated water. It has raised concerns about the environmental health impacts of the co-produced CSG water. In this paper, we review CSG water contaminants and their potential health effects in the context of exposure pathways in Queensland's CSG basins. The hazardous substances associated with CSG water in Queensland include fluoride, boron, lead and benzene. The exposure pathways for CSG water are (1) water used for municipal purposes; (2) recreational water activities in rivers; (3) occupational exposures; (4) water extracted from contaminated aquifers; and (5) indirect exposure through the food chain. We recommend mapping of exposure pathways into communities in CSG regions to determine the potentially exposed populations in Queensland. Future efforts to monitor chemicals of concern and consolidate them into a central database will build the necessary capability to undertake a much needed environmental health impact assessment.

  16. A Combined Micro-CT Imaging/Microfluidic Approach for Understating Methane Recovery in Coal Seam Gas Reservoirs

    Science.gov (United States)

    Mostaghimi, P.; Armstrong, R. T.; Gerami, A.; Lamei Ramandi, H.; Ebrahimi Warkiani, M.

    2015-12-01

    Coal seam methane is a form of natural gas stored in coal beds and is one of the most important unconventional resources of energy. The flow and transport in coal beds occur in a well-developed system of natural fractures that are also known as cleats. We use micro-Computed Tomography (CT) imaging at both dry and wet conditions to resolve the cleats below the resolution of the image. Scanning Electron Microscopy (SEM) is used for calibration of micro-CT data. Using soft lithography technique, the cleat system is duplicated on a silicon mould. We fabricate a microfluidic chip using Polydimethylsiloxane (PDMS) to study both imbibition and drainage in generated coal structures for understating gas and water transport in coal seam reservoirs. First, we use simple patterns observed on coal images to analyse the effects of wettability, cleat size and distribution on flow behaviour. Then, we study transport in a coal by injecting both distilled water and decane with a rate of 1 microliter/ min into the fabricated cleat structure (Figure 1), initially saturated with air. We repeat the experiment for different contact angles by plasma treating the microfluidic chip, and results show significant effects of wettability on the displacement efficiency. The breakthrough time in the imbibition setup is significantly longer than in the drainage. Using rapid video capturing, and high resolution microscopy, we measure the saturation of displacing fluid with respect to time. By measuring gas and liquid recovery in the outlet at different saturation, we predict relative permeability of coal. This work has important applications for optimising gas recovery and our results can serve as a benchmark in the verification of multiphase numerical models used in coal seam gas industry.

  17. Pyrolysis of brown coal mixed with heavy products of coal and petroleum processing

    Energy Technology Data Exchange (ETDEWEB)

    Vikhorev, A.A.; Syroezhko, A.M.; Proskuryakov, V.A.; Akhmedov, N.A.

    1987-03-01

    Investigates effect of various additives on yield of liquid product from pyrolysis of Kansk-Achinsk (Berezovsk deposit) brown coal mixed with organic additives: waste from caprolactam plant consisting mostly of saturated oxygen containing compounds and mono- and di-carboxylic acid esters, waste from sabatic acid plant consisting predominantly of unsaturated acids, distillation residue of synthetic fatty acids, heavy residue from Arlansk oil refineries containing mainly condensed naphtheno-aromatic systems and heavy tar from rapid pyrolysis of Kansk-Achinsk coal. Finds that joint pyrolysis of brown coal with organic additives increases yield of liquid products and that intensive decomposition begins at lower temperatures. 4 refs.

  18. Geochemistry and Modes of Occurrence of Hazardous Trace Elements in the No.11 Coal Seam, Antaibao Surface Mine, Shanxi Province

    Institute of Scientific and Technical Information of China (English)

    SONG Dangyu; QIN Yong; WANG Wenfeng; ZHANG Junying; ZHENG Chuguang

    2007-01-01

    Concentrations of seventeen hazardous trace elements including As, Pb, Hg, Se, Cd, Cr, Co,Mo, Mn, Ni, U, V, Th, Be, Sb, Br and Zn in the No.11 coal seam, Antaibao surface mine, Shanxi Province were determined using Instrumental Neutron Activation Analysis (INAA), Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), Cold-Vapor Atomic Absorption Spectrometry (CV-AAS) and Graphite Furnace Atomic Absorption Spectrometry (GF-AAS).Comparisons with average concentrations of trace elements in Chinese coal show that the concentrations of Hg and Cd in the No. 11 coal seam, Antaibao surface mine are much higher. They may be harmful to the environment in the process of utilization. The variations of the trace elements contents and pyritic sulfur in vertical section indicated that: (a) the concentrations of As, Pb, Mn, and pyritic sulfur decrease from roof to floor; (b) the concentrations of Cr, Zn and Mo are higher in roof,floor and lower in coal seam; (c) the concentration of Br, Sb, and Hg are higher in coal seam and lower in roof and floor; (d) the concentrations of Mo, V, Th and Al vary consistently with the ash yield.Cluster analysis of trace elements, pyritic sulfur, ash yield and major elements, such as Al, Fe, P, Ca shows that: (a) pyritic sulfur, Fe, As, Mn, Ni, Be are closely associated and reflect the influence of pyrite; (b) Mo, Se, Pb, Cr, Th, Co, Ca and Al are related to clay mineral, which is the main source of ash; (c) U, Zn, V, Na, P maybe controlled by phosphate or halite; (d) Hg, Br, Sb and Cd may be mainly organic-associated elements which fall outside the three main groups. The concentration distribution characteristics of trace elements in coal seam and the cluster analysis of major and trace elements showed that the contents of trace elements in the No. 11 coal seam, Antaibao surface mine, are mainly controlled by detrital input and migration from roof and floor.

  19. Draft Genome Sequence of Methanobacterium sp. Maddingley, Reconstructed from Metagenomic Sequencing of a Methanogenic Microbial Consortium Enriched from Coal-Seam Gas Formation Water.

    Science.gov (United States)

    Rosewarne, Carly P; Greenfield, Paul; Li, Dongmei; Tran-Dinh, Nai; Midgley, David J; Hendry, Philip

    2013-01-01

    The draft genome of Methanobacterium sp. Maddingley was reconstructed from metagenomic sequencing of a methanogenic microbial consortium enriched from coal-seam gas formation water. It is a hydrogenotrophic methanogen predicted to grow using hydrogen and carbon dioxide.

  20. An evaluation of deep thin coal seams and water-beating/resisting layers in the quaternary system using seismic inversion

    Institute of Scientific and Technical Information of China (English)

    XU Yong-zhong; HUANG Wei-chuan; CHEN Tong-jun; CUI Ruo-fei; CHEN Shi-zhong

    2009-01-01

    Non-liner wave equation inversion, wavelet analysis and artificial neural networks were used to obtain stratum parame-ters and the distribution of thin coal seams. The lithology of the water-bearing/resisting layer in the Quaternary system was also predicted. The implementation process included calculating the well log parameters, stratum contrasting the seismic data and the well logs, and extracting, studying and predicting seismic attributes. Seismic inversion parameters, including the layer velocity and wave impedance, were calculated and effectively used for prediction and analysis. Prior knowledge and seismic interpretation were used to remedy a dearth of seismic data during the inversion procedure. This enhanced the stability of the inversion method. Non-linear seismic inversion and artificial neural networks were used to interpret coal seismic lithology and to study the wa-ter-bearing/resisting layer in the Quaternary system. Interpretation of the 1-2 m thin coal seams, and also of the wa-ter-bearing/resisting layer in the Quaternary system, is provided. The upper mining limit can be lifted from 60 m to 45 m. The pre-dictions show that this method can provide reliable data useful for thin coal seam exploitation and for lifting the upper mining limit, which is one of the principles of green mining.

  1. Critical hydraulic pressure forecasting of water inrush in coal seam floors based on a genetic algorithm-neural network

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, M.; Shi, C.; Liu, T. [China Academy of Safety Science and Technology, Beijing (China); Fu, T. [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering

    2008-08-15

    This paper presented a method of forecasting water inrush in coal seam floors. The theoretical forecasting method used a combined genetic algorithm-neural network method to analyze the relationships between the critical pressure of water inrush and the different conditions in coal seam floors. Actual measurement data from Chinese coal mines were used to train the multi-layer feedforward neural network. Genetic algorithms were used to train the neural networks and optimize the neural network topology. The topology structure of the network was selected by considering population size, mutation rate, and crossing rates. The critical hydraulic pressure of water inrush was then predicted, and predictions were compared with measurements taken to validate the method. Results of the study showed that the forecasting method improved learning efficiency and the prediction capacity of the network. It was concluded that the combined method can be used to accurately predict the critical hydraulic pressure of water inrush on coal seam floors. 28 refs., 1 tab., 7 figs.

  2. Efficient direct coal liquefaction of a premium brown coal catalyzed by cobalt-promoted fumed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Trautmann, M.; Loewe, A.; Traa, Y. [Stuttgart Univ. (Germany). Inst. of Chemical Technology

    2013-11-01

    The search for alternatives in the fuel sector is an important technological challenge. An interim solution could be provided by direct coal liquefaction. Hydrogen economy and the lack of an efficient catalyst are the main obstacles for this process. We used a premium German brown coal with a high H/C molar ratio of 1.25 and nanostructured cobalt catalysts to improve the efficiency of direct coal liquefaction. We were able to recover and recycle the catalyst efficiently and reached good brown coal conversions and oil yields with single-stage coal liquefaction. The oil quality observed almost reached that of a conventional crude oil considering higher heating value (HHV), H/C molar ratio and aliphatic content. (orig.)

  3. Evolution of a mining induced fracture network in the overburden strata of an inclined coal seam

    Institute of Scientific and Technical Information of China (English)

    Wei; Xiujun; Gao; Mingzhong; Lv; Youchang; Shi; Xiangchao; Gao; Hailian; Zhou; Hongwei

    2012-01-01

    The geological conditions of the Pingdingshan coal mining group were used to construct a physical model used to study the distribution and evolution of mining induced cracks in the overburden strata.Digital graphics technology and fractal theory are introduced to characterize the distribution and growth of the mining induced fractures in the overburden strata of an inclined coal seam.A relationship between fractal dimension of the fracture network and the pressure in the overburden strata is suggested.Mining induced fractures spread dynamically to the mining face and up into the roof as the length of advance increases.Moreover,the fractal dimension of the fracture network increases with increased mining length,in general,but decreases during a period from overburden strata separation until the main roof collapses.It is a1so shown that overburden strata pressure plays an important role in the evolution of mining induced fractures and that the fractal dimension of the fractures increases with the pressure of the overburden.

  4. Wide pillar roadway retained in the deep high gas coal seam

    Institute of Scientific and Technical Information of China (English)

    Pan; Liyou; Feng; Enhu; Zhao; Qingshou; Chen; Liqiang; Kong; Fanpeng

    2012-01-01

    According to the geological and mining conditions of deep high gas coal seam,this paper established the mechanical model of stope surrounding rock,and analyzed the stress distribution and deformation failure mechanism of working face and coal pillar.The research determined the arrangement mode that adjacent working faces retain wide pillar,and the reasonable support method of roadway that the combined support of roof and grouting combined together.The reasonable time of reinforced roadway was determined.Through analyzing the mechanical model of the ways of roadway supporting,this research drew the conclusions as follows:the combined support of roof and working slope improved the support strength and range of surrounding rock,optimized the support by adjusting the angle of anchor,and reached the support requirements by using cement grouting in working slope and chemical grout in roof.The technology was applied in 15104 working face of Baoan Mine,and obtained good results.

  5. The Complex Function Method Roadway Section Design of the Soft Coal Seam

    Directory of Open Access Journals (Sweden)

    Shihao Tu

    2016-01-01

    Full Text Available As for the sophisticated advanced support technique of vertical wall semicircle arch roadway in the three-soft coal seam, a design of flat top U-shape roadway section was put forward. Based on the complex function method, the surrounding rock displacement and stress distribution laws both of vertical wall semicircle arch roadway and of flat top U-shape roadway were obtained. The results showed that the displacement distribution laws in the edge of roadway surrounding rock were similar between the two different roadways and the area of plasticity proportion of flat top U-shape roadway approximately equals that of vertical wall semicircle arch roadway. Based on finite element method, the bearing behaviors of the U-type steel support under the interaction of surrounding rock in vertical wall semicircle arch roadway and flat top U-shape roadway were analyzed. The results showed that, from a mechanics perspective, U-type steel support can fulfill the requirement of surrounding rock supporting in flat top U-shape roadway and vertical wall semicircle arch roadway. The field measurement of mining roadway surrounding rock displacement in Zouzhuang coal mine working face 3204 verified the accuracy of theoretical analysis and numerical simulation.

  6. The adjusting mining technology of combining fully mechanized with individual prop, rotating, hilt, irregular form, and double unit face on thin coal seam of Tianchen Mine

    Institute of Scientific and Technical Information of China (English)

    SONG Hua-ling; WEN Guo-feng; LI Jin-ke

    2008-01-01

    Analyzed the situations and characteristics of thin coal seam mining and its mining technologies, and introduced the mining innovation technology used by Tianchen Coal Mine of Zhaozhuang Coal Company of China. This innovation technology combined the fully mechanized mining with individual props, and the working face of mining is over length, irregular form and double units. The rotational adjusting mining technology on thin coal seam is also practiced in this new mining technology. The detail technologies, such as outlays of working face and ways, mining methods, equipments of cutting, transporting and sporting, have been introduced. So that, using the synthetic and creative mining tech-nologies, Tianchen Coal Mine solves the mining problems of thin coal seam successfully.

  7. Characterization and evaluation of washability of Alaskan coals: Fifty selected seams from various coal fields: Final technical report, September 30, 1976-February 28, 1986. [50 coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Rao, P.D.

    1986-09-01

    This final report is the result of a study initiated in 1976 to obtain washability data for Alaskan coals, to supplement the efforts of the US Department of Energy in their ongoing studies on washability of US coals. Washability characteristics were determined for fifty coal samples from the Northern Alaska, Chicago Creek, Unalakleet, Nenana, Matanuska, Beluga, Yentna and Herendeen Bay coal fields. The raw coal was crushed to 1-1/2 inches, 3/8 inch, 14 mesh and 65 mesh top sizes, and float-sink separations were made at 1.30, 1.40 and 1.60 specific gravities. A limited number of samples were also crushed to 200 and 325 mesh sizes prior to float-sink testing. Samples crushed to 65 mesh top size were also separated at 1.60 specific gravity and the float and sink products were characterized for proximate and ultimate analyses, ash composition and ash fusibility. 72 refs., 79 figs., 57 tabs.

  8. Top coal flows in an excavation disturbed zone of high section top coal caving of an extremely steep and thick seam

    Institute of Scientific and Technical Information of China (English)

    Miao Shengjuna; Lai Xingping; Cui Feng

    2011-01-01

    Compared with gentle dip long-wall caving, the length of a working face in fully-mechanized top-coal caving for extremely steep and thick seams is short, while its horizontal section is high with increasing production. But the caving ratio is low, which might result in some disasters, such as roof falls, induced by local and large area collapse of the top coal in a working face and dangers induced by gas accumulation. After the development of cracks and weakening of the coal body, the tall, broken section of the top coal (a granular medium) of an extremely steep seam (over 60°) shows clear characteristics of nonlinear movement, We have thoroughly analyzed the geological environment and mining conditions of an excavation disturbed zone. Based on the results from a physical experiment of large-scale 3D modeling and coupling simulation of top coal-water-gas, we conclude that the weakened top coal can be regarded as a non-continuous medium. We used a particle flow code program to compare and analyze migration processes and the movements of a 30 m high section top coal over time before and after weakening of an extremely steep seam in the Weihuliang coal mine. The results of our simulation,experiment and monitoring show that pre-injection of water and pre-splitting blasting improve caving ability and symmetrical caving, relieve space for large area dynamic collapse of top coal, prolong migration time of noxious gases and release them from the mined out area and so achieve safety in mining.

  9. Outburst control in soft and outburst prone coal seam using the waterjet slotting technique from modeling to field work

    Institute of Scientific and Technical Information of China (English)

    LU Ting-kan; YAO Zai-feng; CHANG Fang-tao; ZHAO Zhi-jian

    2012-01-01

    The paper discussed a comprehensive numerical simulation and field work by the usage of waterjet slotting technique to prevent the occurrence of outbursts in soft and outburst prone coal seams.This was based on the geological and geomechanical conditions of Jinjiachong Colliery,Guizhou Province,associated with varied waterjet slotting parameters such as slotting penetration,slotting thickness and slotting distance along the length of borehole.Also,to understand the variation of internal stress of coal seams after waterjet slotting application,the internal stress levels were compared with and without slotting application,and the results indicate that the internal effective stress levels can be reduced to 70% and 45% for the vertical and horizontal stresses,respectively,and the gas concentration can be increased up to 5 times when the waterjet slotting is applied.

  10. Membrane solutions for coal seam methane produced water : case history at Origin Energy, Spring Gully Gas Plant, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Wines, T. [Pall Corp., Port Washington, NY (United States); Blyth, G.; Chalmers, S. [Pall Australia, Melbourne (Australia); Karlapudi, R. [Pall Industrial Water, Port Washington, NY (United States)

    2009-07-01

    Coal seam methane is a significant and emerging source of energy that can be found in Australia, western Canada, the United States, China and India. However, the extraction of methane from coal seams has one particular problem whereby, in many cases, large volumes of water with high levels of dissolved salts are produced along with the gas. This produced water poses an environmental liability, but with proper treatment can be converted into an asset. This paper discussed the use of an integrated membrane system (IMS) consisting of microfiltration coupled with reverse osmosis filtration. A case history at Origin Energy was evaluated where pilot testing was first conducted and later followed by a commercial installation treating nine million liters per day, creating a purified water product that can be used for industrial processes as well as irrigation or discharge into the environment. The paper also presented lessons learned from the pilot phase and explained the experience of the full scale operation demonstrating the advantages of this newly applied technology for coal seam methane production. The IMS system has met Origin Energy's requirements for producing high quality water, and has continued to operate effectively, producing treated water that is well within the Queensland Environmental Protection Agency's guidelines. 6 refs., 1 tab., 11 figs.

  11. Application of pressure relief and permeability increased by slotting a coal seam with a rotary type cutter working across rock layers

    Institute of Scientific and Technical Information of China (English)

    Shen Chunming; Lin Baiquan; Meng Fanwei; Zhang Qizhi; Zhai Cheng

    2012-01-01

    Pressure relief to increase permeability significantly improves gas extraction efficiency from coal seams.In this paper we report results from simulations using FLAC3D code to analyze changes in coal displacement and stress after special drill slots were formed.We investigated the mechanism of pressure relief and permeability increase in a high-gas and low-permeability coal seam through the modeling of gas flow.This allows the development of the technology.Slotting across rock layers in the coal seam with a rotary type cutter was then applied in the field.The results show that pressure relief and permeability increases from slotting the coal seam can increase the transport and the fracture of the coal.This expands the range of pressure relief from the drilling and increases the exposed area of the seam.The total quantity of gas extracted from slotted bore holes was three times that seen with ordinary drilling.The concentration of gas extracted from the slotted drills was from two to three times that seen using ordinary drills.The gas flow was stable at 80%.Improved permeability and more efficient gas extraction are the result of the slotting.The roadway development rate is increased by 30-50% after gas drainage.This technology diminishes the lag between longwall production and roadway development and effectively prevents coal and gas outburst,which offers the prospect of broad application.

  12. Analysis of the Harmfulness of Water-Inrush from Coal Seam Floor Based on Seepage Instability Theory

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A theory of seepage instability was used to estimate the harmfulness of water-inrush from a coal seam floor in a particular coal mine of the Mining Group, Xuzhou.Based on the stratum column chart in this coal mine, the distribution of stress in mining floors when the long-wall mining was respectively pushed along to 100 m and to 150 m was simulated by using the numerical software (RFPA2D).The permeability parameters of the coal seam floor are described given the relationship between permeability parameters.Strain and the water-inrush-indices were calculated.The water-inrush-index was 67.2% when the working face was pushed to 100 m, showing that water-inrush is possible and it was 1630% when the working face was pushed to 150 m, showing that water-inrush is quite probable.The results show that as long-wall mining is pushed along, the failure zone is enlarged, the strain increased, and fissures developed correspondingly, resulting in the formation of water-inrush channels.Accompanied by the failure of the strata, the permeability increased exponentially.In contrast, the non-Darcy flow β factor and the acceleration coefficient decreased exponentially, while the increase in the water-inrush-index was nearly exponential and the harmfulness of water-inrush in the coal mine increased accordingly.

  13. Method of mining heavy coal seams in two or more benches

    Energy Technology Data Exchange (ETDEWEB)

    Barsi, K.; Dorombozi, L.; Forisek, I.; Kuburczik, G.; Stuber, G.

    1982-07-20

    In mining a heavy coal seam that must be excavated in several benches, the excavation of the uppermost bench is accompanied by the introduction of a cementitious slurry into the resulting stope for consolidating the waste rock present therein, preparatorily to the excavation of the next-lower bench, and proceeding in like manner with the second bench if a third one is to follow. The cementitious slurry comprises burnt or slaked lime, and/or Portland cement, suspended in water in a quantity of about 10 to 60% by weight and preferably together with a small percentage of chlorides of one or more alkali or alkaline-earth metals, to which ceramic aggregates at large specific surface such as mineral ashes, slag, sand or dolomite powder may be added in a quantity of up to about 30% of the weight of the water. The slurry, on being admitted to the stope in an amount of at least 10% of the volume thereof, causes the waste rock to swell and form a solid layer of up to approximately a meter in thickness which allows the next-lower bench to be excavated after only about a month's delay.

  14. Variable frequency of pulse hydraulic fracturing for improving permeability in coal seam

    Institute of Scientific and Technical Information of China (English)

    Li Quangui; Lin Baiquan; Zhai Cheng; Ni Guanhua; Peng Shen; Sun Chen; Cheng Yanying

    2013-01-01

    Variable frequency, a new pattern of pulse hydraulic fracturing, is presented for improving permeability in coal seam. A variable frequency pulse hydraulic fracturing testing system was built, the mould with triaxial loading was developed. Based on the monitor methods of pressure sensor and acoustic emission, the trials of two patterns of pulse hydraulic fracturing of single frequency and variable frequency were carried out, and at last fracturing mechanism was analyzed. The results show that the effect of variable frequency on fracture extension is better than that of single frequency based on the analysis of macro-scopic figures and AE. And the shortage of single frequency is somewhat remedied when the frequency is variable. Under variable frequency, the pressure process can be divided into three stages: low fre-quency band, pressure stability band and high frequency band, and rupture pressure of the sample is smaller than that of the condition of single frequency. Based on the Miner fatigue theory, the effect of different loading sequences on sample rupture is discussed and the results show that it is better to select the sequence of low frequency at first and then high frequency. Our achievements can give a basis for the improvement and optimization of the pulse hydraulic fracturing technology.

  15. Mechanical model of water inrush from coal seam floor based on triaxial seepage experiments

    Institute of Scientific and Technical Information of China (English)

    Yihui Pang; Guofa Wang; Ziwei Ding

    2014-01-01

    In order to study the mechanism of confined water inrush from coal seam floor, the main influences on permeability in the process of triaxial seepage experiments were analyzed with methods such as laboratory experiments, theoretical analysis and mechanical model calculation. The crack extension rule and the ultimate destruction form of the rock specimens were obtained. The mechanism of water inrush was explained reasonably from mechanical point of view. The practical criterion of water inrush was put forward. The results show that the rock permeability ‘‘mutation’’ phe-nomenon reflects the differences of stress state and cracks extension rate when the rock internal crack begins to extend in large-scale. The rock ultimate destruction form is related to the rock lithology and the angle between crack and principal stress. The necessary condition of floor water inrush is that the mining pressure leads to the extension and transfixion of the crack. The sufficient condition of floor water inrush is that the confined water’s expansionary stress in normal direction and shear stress in tangential direction must be larger than the internal stress in the crack. With the two conditions satisfied at the same time, the floor water inrush accident will occur.

  16. Chemical variability of groundwater samples collected from a coal seam gas exploration well, Maramarua, New Zealand.

    Science.gov (United States)

    Taulis, Mauricio; Milke, Mark

    2013-03-01

    A pilot study has produced 31 groundwater samples from a coal seam gas (CSG) exploration well located in Maramarua, New Zealand. This paper describes sources of CSG water chemistry variations, and makes sampling and analytical recommendations to minimize these variations. The hydrochemical character of these samples is studied using factor analysis, geochemical modelling, and a sparging experiment. Factor analysis unveils carbon dioxide (CO(2)) degassing as the principal cause of sample variation (about 33%). Geochemical modelling corroborates these results and identifies minor precipitation of carbonate minerals with degassing. The sparging experiment confirms the effect of CO(2) degassing by showing a steady rise in pH while maintaining constant alkalinity. Factor analysis correlates variations in the major ion composition (about 17%) to changes in the pumping regime and to aquifer chemistry variations due to cation exchange reactions with argillaceous minerals. An effective CSG water sampling program can be put into practice by measuring pH at the wellhead and alkalinity at the laboratory; these data can later be used to calculate the carbonate speciation at the time the sample was collected. In addition, TDS variations can be reduced considerably if a correct drying temperature of 180 °C is consistently implemented.

  17. Atmospheric radon, CO2 and CH4 dynamics in an Australian coal seam gas field

    Science.gov (United States)

    Tait, D. R.; Santos, I. R.; Maher, D. T.

    2013-12-01

    Atmospheric radon (222Rn), carbon dioxide (CO2), and methane concentrations (CH4) as well as carbon stable isotope ratios (δ13C) were used to gain insight into atmospheric chemistry within an Australian coal seam gas (CSG) field (Surat Basin, Tara region, Queensland). A˜3 fold increase in maximum 222Rn concentration was observed inside the gas field compared to outside of it. There was a significant relationship between maximum and average 222Rn concentrations and the number of gas wells within a 2 km to 4 km radius of the sampling sites (n = 5 stations; p gas field related to point sources (well heads, pipelines, etc.) and diffse soil sources due to changes in the soil structural and hydrological characteristics. A rapid qualitative assessment of CH4 and CO2 concentration, and carbon isotopes using a mobile cavity ring-down spectrometer system showed a widespread enrichment of both CH4 and CO2 within the production gas field. Concentrations of CH4 and CO2 were as high as 6.89 ppm and 541 ppm respectively compared average concentrations of 1.78 ppm (CH4) and 388 ppm (CO2) outside the gas field. The δ13C values showed distinct differences between areas inside and outside the production field with the δ13C value of the CH4 source within the field matching that of the methane in the CSG.

  18. The effect of zeolite treatment by acids on sodium adsorption ratio of coal seam gas water.

    Science.gov (United States)

    Wang, Xiaoyu; Ozdemir, Orhan; Hampton, Marc A; Nguyen, Anh V; Do, Duong D

    2012-10-15

    Many coal seam gas (CSG) waters contain a sodium ion concentration which is too high relative to calcium and magnesium ions for environment acceptance. Natural zeolites can be used as a cheap and effective method to control sodium adsorption ratio (SAR, which is a measure of the relative preponderance of sodium to calcium and magnesium) due to its high cation exchange capacity. In this study, a natural zeolite from Queensland was examined for its potential to treat CSG water to remove sodium ions to lower SAR and reduce the pH value. The results demonstrate that acid activated zeolite at 30%wt solid ratio can reduce the sodium content from 563.0 to 182.7 ppm; the pH from 8.74 to 6.95; and SAR from 70.3 to 18.5. Based on the results of the batch experiments, the sodium adsorption capacity of the acid-treated zeolite is three times greater than that of the untreated zeolite. Both the untreated and acid-treated zeolite samples were characterized using zeta potential, surface characterization, DTA/TG and particle size distribution in order to explain their adsorption behaviours.

  19. Deformation effect of lateral roof roadway in close coal seams after repeated mining

    Institute of Scientific and Technical Information of China (English)

    Xie Jianlin; Xu Jialin; Wang Feng; Guo Jiekai; Liu Donglin

    2014-01-01

    This paper analyzed the deformation mechanism in lateral roof roadway of the Ding Wu-3 roadway which was disturbed by repeated mining of close coal seams Wu-8 and Wu-10 in Pingdingshan No. 1 Mine. To determine the strata disturbance scope, the strata displacement angle was used to calculate the protection pillar width. A numerical model was built considering the field geological conditions. In simulation, the mining stress borderline was defined as the contour where the induced stress is 1.5 times of the original stress. Simulation results show the mining stress borderline of the lateral roadway extended 91.7 m outward after repeated mining. Then the original stress increased, deforming the road-way of interest. This deformation agreed with the in situ observations. Moreover, the strata displacement angle changed due to repeated mining. Therefore, reselection of the displacement angle was required to design the protective pillar width. Since a constant strata displacement angle was used in traditional design, the proposed method was beneficial in field cases.

  20. Time-lapse analysis of methane quantity in Mary Lee group of coal seams using filter-based multiple-point geostatistical simulation

    Science.gov (United States)

    Karacan, C. Özgen; Olea, Ricardo A.

    2013-01-01

    Coal seam degasification and its success are important for controlling methane, and thus for the health and safety of coal miners. During the course of degasification, properties of coal seams change. Thus, the changes in coal reservoir conditions and in-place gas content as well as methane emission potential into mines should be evaluated by examining time-dependent changes and the presence of major heterogeneities and geological discontinuities in the field. In this work, time-lapsed reservoir and fluid storage properties of the New Castle coal seam, Mary Lee/Blue Creek seam, and Jagger seam of Black Warrior Basin, Alabama, were determined from gas and water production history matching and production forecasting of vertical degasification wellbores. These properties were combined with isotherm and other important data to compute gas-in-place (GIP) and its change with time at borehole locations. Time-lapsed training images (TIs) of GIP and GIP difference corresponding to each coal and date were generated by using these point-wise data and Voronoi decomposition on the TI grid, which included faults as discontinuities for expansion of Voronoi regions. Filter-based multiple-point geostatistical simulations, which were preferred in this study due to anisotropies and discontinuities in the area, were used to predict time-lapsed GIP distributions within the study area. Performed simulations were used for mapping spatial time-lapsed methane quantities as well as their uncertainties within the study area.

  1. Geochemical Characteristics of Trace Elements in the No. 6 Coal Seam from the Chuancaogedan Mine, Jungar Coalfield, Inner Mongolia, China

    Directory of Open Access Journals (Sweden)

    Lin Xiao

    2016-03-01

    Full Text Available Fourteen samples of No. 6 coal seam were obtained from the Chuancaogedan Mine, Jungar Coalfield, Inner Mongolia, China. The samples were analyzed by optical microscopic observation, X-ray diffraction (XRD, scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (SEM-EDS, inductively coupled plasma mass spectrometry (ICP-MS and X-ray fluorescence spectrometry (XRF methods. The minerals mainly consist of kaolinite, pyrite, quartz, and calcite. The results of XRF and ICP-MS analyses indicate that the No. 6 coals from Chuancaogedan Mine are higher in Al2O3, P2O5, Zn, Sr, Li, Ga, Zr, Gd, Hf, Pb, Th, and U contents, but have a lower SiO2/Al2O3 ratio, compared to common Chinese coals. The contents of Zn, Sr, Li, Ga, Zr, Gd, Hf, Pb, Th, and U are higher than those of world hard coals. The results of cluster analyses show that the most probable carrier of strontium in the coal is gorceixite; Lithium mainly occurs in clay minerals; gallium mainly occurs in inorganic association, including the clay minerals and diaspore; cadmium mainly occurs in sphalerite; and lead in the No. 6 coal may be associated with pyrite. Potentially valuable elements (e.g., Al, Li, and Ga might be recovered as byproducts from coal ash. Other harmful elements (e.g., P, Pb, and U may cause environmental impact during coal processing.

  2. Empirical-analytical method for evaluating the pressure distribution in the hard coal seams

    Institute of Scientific and Technical Information of China (English)

    KABIESZ Józef; MAKóWKA Janusz

    2009-01-01

    At present, numerical modelling of distributions of many rock mass characteristics plays more and more important role in many geomechanical questions. In the issues related to seismic and rockburst hazards, the analyses of distributions of stress component values in the rock strata are performed, similarly as those of deformation parameters of the strata. To do this, commercial computer programs are used which function on the basis of the finite element-, separate element-, finite difference-, boundary element methods, or individually designed computer programs. They enable to obtain information, unattainable with other methods, being of importance for further concluding on those hazards. The programs based on applying those methods have contributed to important progress and development of science in the domain of analyzing and predicting the hazards. To this end, the commercial computer programs are used that are based on the methods of: finite elements, separate elements, finite differences, boundary elements, etc., or on individually developed computer programs. They enable to obtain information, unavailable using other methods, being of vital importance for further concluding on these hazards. The programs based on these methods have contributed to essential progress and development of science in the field of analysing and predicting the hazards. Apart from their obvious advantages, they have many drawbacks that hinder their practical, routine application. To allow making these type of analyses, without the necessity of constructing complicated models and knowing the detailed geomechanical parameters of rocks, together with laborious computation using a high-rank computer hardware, an analytical-empirical method has been developed at Central Mining Institute, Poland, to make prediction (modelling) of the distribution of pressure values (vertical component of stress) in SIGMAZ coal seams. It is based on geophysical measurements, generalized for the conditions of

  3. Complex methods to determine zones liable to sudden outbursts during prospecting and mining of gassy coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Sergeev, I.V.; Ivanov, B.M. [Skochinsky Institute of Mining, Lyubertsy (Russian Federation)

    1995-12-31

    Greater depth of mining and speed of development driving results in greater number of coal seams liable to outbursts. A concept for coal and gas outbursts prevention worked out in Russia provides the main idea and a practical combination of a reliable forecast of the zones liable to outbursts with optimum parameters for the technological impact on the mining of gassy coal seams. The main idea for a reliable forecast of the coal seam zones liable to outbursts allows a complex estimation of the potential outburst hazard outside the mine development impact zone depending upon the geological and geophysical investigations of the prospecting boreholes and true outburst hazard as a function of the potential outburst hazard and energy capacity and its effects upon the technology of the development of faces. Main idea of complex forecast can be developed by forming a criteria for the outburst hazard which is a function of the basic outburst hazard factors conditioned by the energy-power theory for sudden outbursts. The basic outburst hazard factors are considered as a function of empirical outburst hazard indices which make it possible to determine the forecast criteria on a statistical basis by using computers and the image recognition theory. It is possible to develop a regional (geological prospecting) and a local (periodical - in the development faces) forecast of the outburst hazard zones, and to determine the reduction degree for gas content and gas pressure on applying anti-outburst measures. Resorting to the seismoacoustic (apparatus ZUA type) and gas-dynamic (methane-control equipment) automated forecasting makes it possible to continuously control the reactions of the near-face rock mass to the technological influence. The information through the telemetry reaches the mine computer at the switchboard and is translated into a forecast. 1 tab.

  4. Rheological Behaviors of Bio-degradable Drilling Fluids in Horizontal Drilling of Unconsolidated Coal Seams

    Directory of Open Access Journals (Sweden)

    Cai Jihua

    2011-06-01

    Full Text Available In China, horizontal drilling techniques have been widely used in the exploration of coalbed methane (CBM. The drill-in fluids, especially in unconsolidated coal seams, are typically comprised of cellulose polymers, xanthan polymers and guar gums. However, testing and experience have shown that insufficient degradation of filter cakes resulting from even this “clean” drill-in fluids can significantly impede flow capacity at the wellbore wall. Past approaches to minimizing the damage have been the application of strong acids or oxidative breakers systems. They are often only marginally successful, particularly when applied in extended length intervals. Therefore, this paper introduced an engineered technique incorporating non-toxic, environment friendly and economically attractive bio-degradable drilling fluids (BDF.Extensive lab tests were conducted to evaluate the effects of substrate (polymer type, substrate concentration, enzyme type and enzyme concentration on the viscosity breaking behaviors of BDFs. We got the conclusions as follows. (1 Power Law model was the best model to matching the rheological properties of BDFs; (2 Compared with konjak, the degradations of Na-CMC and guar gum were easier to be controlled; (3 In the degradation of CMC by enzyme SE-1, the optimal weight concentration ratio of CMC to SE-1 was 3 to 1; (4 Of the three enzymes, enzyme SE-2 had the highest activity and could be used to degrade polymer in shorter time; (5 Higher enzyme concentration could speed up the degradation reaction; (6 Viscosity breaking times fluctuating from 13.5 hours to 74.5 hours and viscosity breaking ratios varying from 20% to 100% could be achieved by modifying the formulations of BDFs.

  5. Pore pressure propagation in a permeable thin-layer coal seam based on a dual porosity model: A case of risk prediction of water inrush in coalmines

    Science.gov (United States)

    Zhu, B.; Gao, F.; Yang, J. W.; Zhou, G. Q.

    2016-08-01

    Thin-layer coal seams, a type of filling coal rock body, are considered aquifer systems made up of dual porosity medium with immediate floor. A numerical simulation for the pore pressure propagation along a thin-layer coal seam was carried out for the case of the Zhaogezhuang coalmine in China. By valuing the permeability (Kf ) of the thin-layer coal seam, pore pressure variation with time was simulated and compared to the analytical solutions of a dual porosity model (DPM). The main conclusions were drawn as follow: (1) Seepage in the thin-layer coal seam was predominant in the whole process, and the distance of seepage was lengthened and the pore pressure decreased with increased Kf , (2) A series of simulated hydraulic graphs demonstrated that the pore pressure characteristics of peak-occurring and time-lag effects agreed with the analytical solutions of DPM; (3) By adjusting the parameters of DPM, two results of analytical solutions and numerical solutions fit well, particularly in the thin-layer coal seam, (4) The power law relationship between the peak-values and lag time of pore pressure were derived statistically under consideration of the Kf parameter in the range of 10-8 to 10-10 m2/pa-s orders, and it was reasonable that the Kf of the thin-layer coal seam was in the range of 10-8 m2/pa-s orders. The results were significantly helpful in decision-making for mining water prevention and prediction in practice.

  6. 保护层开采被保护层卸压增透效果的应用研究%Effect of protective seam mining on pressure relief and permeability enhancement of protected coal seam

    Institute of Scientific and Technical Information of China (English)

    冯拥军; 周玉军; 张喜传

    2014-01-01

    In view of the coal seam occurrence condition and geological condition of the west-ern region of Henan Province,the gas pressure releasing and drainage in protective coal seam was designed and the drilling design was investigated. In addition,the gas parameters and the dis-placement of roof and floor of B1 coal seam were determined. The research results showed that after the protective seam mining,coal seam gas pressure was decreased from the original 0.9 MPa to 0.12 MPa,the original gas content was reduced from the previous 6.52 m3/t to 3.1 m3/t,the expansion deformation of roof and floor reached 20.6 ‰,and the coal seam permeability coefficient was increased 810 times,so that the outburst danger at No. 12112 working face of B1 coal seam was eliminated in the pressure released area.%针对豫西煤田煤层赋存情况及地质状况,设计了被保护层的卸压抽采方案及考察钻孔,对瓦斯基础参数和二1煤层的煤层顶底板移近量进行了测定.研究结果表明,二1煤层在受到保护层开采后,煤层瓦斯压力由原始的0.9 MP a降为0.12 MP a ,原始瓦斯含量由以前的6.52 m3/t降为3.1 m3/t,顶底板膨胀变形量达到20.6‰,煤层透气性系数增大了810倍,在卸压区内完全消除了二1煤层12112工作面的突出危险性.

  7. Sensitivity of detection of fugitive methane emissions from coal seam gas fields

    Science.gov (United States)

    Feitz, A. J.; Berko, H.; Wilson, P.; Jenkins, C.; Loh, Z. M.; Etheridge, D.

    2013-12-01

    There is increasing recognition that minimising methane emissions from the oil and gas sector is a key step in reducing global greenhouse gas emissions in the near term. Atmospheric monitoring techniques are likely to play an important future role in measuring the extent of existing emissions and verifying emission reductions. They can be very suitable for monitoring gas fields as they are continuous and integrate emissions from a number of potential point and diffuse sources that may vary in time. Geoscience Australia and CSIRO Marine & Atmospheric Research have collected three years of continuous methane and carbon dioxide measurements at their atmospheric composition monitoring station ('Arcturus') in the Bowen Basin, Australia. Methane signals in the Bowen Basin are likely to be influenced by cattle production, landfill, coal production, and conventional and coal seam gas (CSG) production. Australian CSG is typically 'dry' and is characterised by a mixed thermogenic-biogenic methane source with an absence of C3-C6+ alkanes. The range of δ13C isotopic signatures of the CSG is similar to methane from landfill gas and cattle emissions. The absence of standard in-situ tracers for CSG fugitive emissions suggests that having a comprehensive baseline will be critical for successful measurement of fugitive emissions using atmospheric techniques. In this paper we report on the sensitivity of atmospheric techniques for the detection of fugitive emissions from a simulated new CSG field against a three year baseline signal. Simulation of emissions was performed for a 1-year period using the coupled prognostic meteorological and air pollution model TAPM at different fugitive emission rates (i.e. estimates of <1% to up to 10% of production lost) and distances (i.e. 10 - 50 km) from the station. Emissions from the simulated CSG field are based on well density, production volumes, and field size typical of CSG fields in Australia. The distributions of the perturbed and

  8. Community perspectives of natural resource extraction: coal-seam gas mining and social identity in Eastern Australia

    Directory of Open Access Journals (Sweden)

    David Lloyd

    2013-01-01

    Full Text Available Using a recent case study of community reaction to proposed coal-seam gas mining in eastern Australia, we illustrate the role of community views in issues of natural resource use. Drawing on interviews, observations and workshops, the paper explores the anti-coal-seam gas social movement from its stages of infancy through to being a national debate linking community groups across and beyond Australia. Primary community concerns of inadequate community consultation translate into fears regarding potential impacts on farmland and cumulative impacts on aquifers and future water supply, and questions regarding economic, social and environmental benefits. Many of the community activists had not previously been involved in such social action. A recurring message from affected communities is concern around perceived insufficient research and legislation for such rapid industrial expansion. A common citizen demand is the cessation of the industry until there is better understanding of underground water system interconnectivity and the methane extraction and processing life cycle. Improved scientific knowledge of the industry and its potential impacts will, in the popular view, enable better comparison of power generation efficiency with coal and renewable energy sources and better comprehension of the industry as a transition energy industry. It will also enable elected representatives and policy makers to make more informed decisions while developing appropriate legislation to ensure a sustainable future.

  9. Pyrolysis of Compositions of Mixtures of Combustible Shales and Brown Coals Deposited in Belarus

    Science.gov (United States)

    Lishtvan, I. I.; Dudarchik, V. M.; Kraiko, V. M.; Belova, Yu. V.

    2013-11-01

    This paper presents the results of investigating the pyrolysis of compositions of mixtures of brown coals and combustible shales in a close-packed and a moving layer and the yield dynamics of the pyrolysis gas and resin. A comparative analysis of the quality of pyrolysis products obtained from combustible shales and brown coal and from their mixtures has been performed.

  10. Numerical analysis of the destruction of water-resisting strata in a coal seam floor in mining above aquifers

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhihai

    2011-01-01

    With the increase in mining depth many mining areas in China have entered a period necessitating mining above aquifers.Production safety in coal mines in northern China is under serious threat from Ordovician karst water on coal seam floors.In order to analyze the destruction of water-resisting strata in floors of coal seams being mined and to achieve safe mining above deep aquifers,we established a numerical model of water-resisting strata,considering the structural characteristics and mechanical properties of a floor layered with hard and soft rock.We simulated the distribution characteristics of deformation,failure and seepage using the analytical module of fluid-structure interaction of FLAC.We also obtained the corresponding stress distribution,deformation and flow vectors.Our results indicate that:(1) the advance of the working face causes water-resisting strata in goaf floors to form a deep double-clamped beam,subject to homogeneous loading at the bottom; (2) the two sides of the rock beam are subject to shear failure; (3) both sides of the rock seam at the bottom of the water-resisting strata are subject to tension and the greater the working face advance,the more serious the failure; (4) the original balance of the stress and seepage fields are broken and redistributed due to mining activities,especially the interaction of the abutment pressure in both sides of the goaf; the lateral pressure on the goaf floor and the water pressure on the floor of the aquifer promote floor heave and shear failure on both sides of the floor,forming a water-inrush passage.Our study results can provide references for the mechanism of water-inrush on mine floors.

  11. Role of tectonic movements in the origin of gas outburst hazards of black coal seams in the Mecsek Area

    Energy Technology Data Exchange (ETDEWEB)

    Nemedi; Varga, Z.

    1985-01-01

    The tectonics and the major structural elements of the lower Liassic black coal seams of the Mecsek Area are reviewed. The folded and faulted tectonic elements play a predominant role in the process of gas migration and trap formation. Since these elements are of primary importance from the point of view of gas outburst hazard, the knowledge of the distribution and peculiarities of these elements is very important. The investigations needed to forecast the gas outbursts both from the local and from the areal point of view are comprehensively discussed.

  12. Determining coal reserves in a mine field, accounting for the random nature of the change in the seam thickness. [USSR

    Energy Technology Data Exchange (ETDEWEB)

    Smirenskii, M.M.; Rozhkova, N.B.

    1979-01-01

    A method is proposed for calculating the balanced coal reserves (shales) based on the probability distribution of values corresponding to the seam thickness. The approval tests for the method, which were performed in accordance with the conditions at the ''Osinnikovsk'' mine of the ''Yuzhkuzbassgol'' Production Union demonstrated that it is no less accurate than traditional methods, while the labor expended and volume of calculations are, on the average, cut in half. Additionally, the proposed method makes it possible to numerically evaluate the reliability of the calculations performed.

  13. Numerical simulation and experiment analysis of improving permeability by deep-hole presplitting explosion in high gassy and low permeability coal seam

    Institute of Scientific and Technical Information of China (English)

    CAI Feng; LIU Ze-gong; LIN Bai-quan; LI Wei

    2009-01-01

    Created a new damage model for explosive for LS-DYNA3D, taking advantage of the Taylor method aimed at the high gassy and low permeability coal seam, and nu-merically simulated and analyzed the deep-hole presplitting explosion. The entire process of explosion was represented, including cracks caused by dynamic pressure, transmission and vibration superposition of stress waves, as well as cracks growth driven by gas gen-erated by explosion. The influence of the cracks generated in the process of explosion and the performance of improving permeability caused by the difference of interval between explosive holes were analyzed. A reasonable interval between explosive holes of deep-hole presplitting explosions in high gassy and low permeability coal seams was proposed, and the resolution of gas drainage in high gassy and low permeability coal seam was put forward.

  14. Brown Coal Dewatering Using Poly (Acrylamide-Co-Potassium Acrylic Based Super Absorbent Polymers

    Directory of Open Access Journals (Sweden)

    Sheila Devasahayam

    2015-09-01

    Full Text Available With the rising cost of energy and fuel oils, clean coal technologies will continue to play an important role during the transition to a clean energy future. Victorian brown coals have high oxygen and moisture contents and hence low calorific value. This paper presents an alternative non evaporative drying technology for high moisture brown coals based on osmotic dewatering. This involves contacting and mixing brown coal with anionic super absorbent polymers (SAP which are highly crossed linked synthetic co-polymers based on a cross-linked copolymer of acryl amide and potassium acrylate. The paper focuses on evaluating the water absorption potential of SAP in contact with 61% moisture Loy Yang brown coal, under varying SAP dosages for different contact times and conditions. The amount of water present in Loy Yang coal was reduced by approximately 57% during four hours of SAP contact. The extent of SAP brown coal drying is directly proportional to the SAP/coal weight ratio. It is observed that moisture content of fine brown coal can readily be reduced from about 59% to 38% in four hours at a 20% SAP/coal ratio.

  15. 急倾斜薄煤层采煤方法发展趋势%On development tendency for coal mining methods of inclined thin seams

    Institute of Scientific and Technical Information of China (English)

    迟学海; 孟鑫

    2016-01-01

    The PaPer introduces the develoPment features of the coal mining methods in the inclined thin seams based on the blasting mining tech-nology,exPlores the develoPment of the hydroPower coal mining and mechanized coal mining,and forecasts the develoPment of the coal mining methods of the inclined thin seams,so as to enhance the oPtimization of the coal mining craft.%介绍了基于炮采工艺的急倾斜薄煤层采煤方法的发展特点,并探讨了水力采煤与机械化采煤的发展现状,预测了急倾斜薄煤层采煤方法的发展趋势,有利于促进采煤工艺的不断优化改进。

  16. Role of igneous rocks in the development of the gas outburst-prone nature of the black coal seams in the Mecsek area

    Energy Technology Data Exchange (ETDEWEB)

    Nemedi Varga, Z.

    1986-01-01

    In addition to the rank and structural conditions of coal seams the role of volcanic dykes is primordial from the point of view of the development of gas outburst of coal seams. The Mesco-Cenozoic volcanism of the Mecsek Mountains (South Transdanubia) is reviewed including the areal distribution of volcanics. The rock types and their frequency of occurrence are described with special emphasis to the contact metamorphism produced by the interaction of igneous and sedimentary rocks. The possibilities of gas migration as a function of the tectonic conditions are outlined exemplified by the Komlo region most famous for its gas outburst events.

  17. Extracting a very thick seam at the Stara Jama mine in Yugoslavia

    Energy Technology Data Exchange (ETDEWEB)

    Bijelic, V.

    1986-01-01

    The Stara Jama mine is located in a brown coal field in the Northern part of the central Bosnian coal reserves. The main seam in the West Field attains an average seam thickness of 13.20 mm. On account of its major thickness, good calorific value and relatively low depth the extraction of the seam is of interest in economic terms. This article describes a fully mechanised longwall installation at Stara Jama mine for the complete extraction of thick coal seams. Analysis of the operating results of this method with the extraction method previously used leads to the conclusion that the longwalling applied at Stara Jama mine in conjunction with the top slicing method facilitates exploitation of the deposit, high operating results and a low safety risk.

  18. Suitable layout of gate roads related to slice mining in an ultra-thick unstable coal seam

    Institute of Scientific and Technical Information of China (English)

    Fan Gangwei; Zhang Dongsheng; Zhou Lei

    2011-01-01

    We determined a suitable gate road layout in slice mining in an ultra-thick unstable coal seam,using theoretical analysis and numerical calculations.Based on plasticity theory in terms of limiting equilibrium,the width of chain pillar in the upper slice was calculated to be 18 m.The stress distribution in the chain pillar after the upper slice was mined out was described with numerical simulation.The extent of the effect of stress on the upper chain pillar on the lower solid coal was obtained on the basis of an elastic solution of a distributed force loaded on a half-plane.Three layout designs for lower gate roads were proposed and a stability factor was introduced to analyze the stability of the lower pillar with numerical calculation.Gate road translation was determined as the most suitable layout method,which maximizes the extraction rate on the basis of the pillar stability.

  19. Induced drill-spray during hydraulic slotting of a coal seam and its influence on gas extraction

    Institute of Scientific and Technical Information of China (English)

    Shen Chunming; Lin Baiquan; Zhang Qizhi; Yang Wei; Zhang Lianjun

    2012-01-01

    Hydraulic slotting can induce drill spray in a gassy,low permeability coal seam.This then influences subsequent gas extraction.This paper describes the drill spray phenomenon from a mechanical perspective and analyzes the effects of water jet damage during slotting.A simulation of the stresses around the drill hole and slot was prepared using FLAC-3D code.It helps explain the induction of drill spray during hydraulic slotting.The stress concentration around the bore increases as the diameter of the hole increases.As the hole enlarges the variation in stress also increases,which introduces an instability into the coal.This allows easy breaking and removal of the coal.Destruction of the coal structure by the water jet is the major factor causing drill spray.Energy stored as either strain or gas pressure is released by the water jet and this causes the coal to fracture and be expelled from the hole.Field tests showed the effect on gas extraction after slotting with drill spray.The concentration of gas increases after drilling.Compared to conventional techniques,the hydraulic slotted bore gives a gas concentration three times higher and has an effective range twice as far.This makes the gas extraction process more efficient and allows reduced construction effort.

  20. A reactive transport modelling approach to assess the leaching potential of hydraulic fracturing fluids associated with coal seam gas extraction

    Science.gov (United States)

    Mallants, Dirk; Simunek, Jirka; Gerke, Kirill

    2015-04-01

    Coal Seam Gas production generates large volumes of "produced" water that may contain compounds originating from the use of hydraulic fracturing fluids. Such produced water also contains elevated concentrations of naturally occurring inorganic and organic compounds, and usually has a high salinity. Leaching of produced water from storage ponds may occur as a result of flooding or containment failure. Some produced water is used for irrigation of specific crops tolerant to elevated salt levels. These chemicals may potentially contaminate soil, shallow groundwater, and groundwater, as well as receiving surface waters. This paper presents an application of scenario modelling using the reactive transport model for variably-saturated media HP1 (coupled HYDRUS-1D and PHREEQC). We evaluate the fate of hydraulic fracturing chemicals and naturally occurring chemicals in soil as a result of unintentional release from storage ponds or when produced water from Coal Seam Gas operations is used in irrigation practices. We present a review of exposure pathways and relevant hydro-bio-geo-chemical processes, a collation of physico-chemical properties of organic/inorganic contaminants as input to a set of generic simulations of transport and attenuation in variably saturated soil profiles. We demonstrate the ability to model the coupled processes of flow and transport in soil of contaminants associated with hydraulic fracturing fluids and naturally occurring contaminants.

  1. A probe into "mining technique in the condition of floor failure" for coal seam above longwall goafs

    Institute of Scientific and Technical Information of China (English)

    FENG Guo-rui; WANG Xian-xia; KANG Li-xun

    2008-01-01

    Targeting at the coal seam with useful value discarded above goafs, attempted to explore the feasibility of "mining technique in the condition of floor failure" from theoretical point of view, and predicted. It indicated that mining technique in the condition of floor failureused above Longwall Goafs in Baijiazhuang Mining is totally feasible. At law, the deformation of the floor in the mining technique by means of probability-integral method. And it is discov-ered that deformed basin can emerge in the footwall of No.6 coal seam and its maximum subsidence was possibly 1 633 mm or so and its maximum positive curvature is 61.74/10-3.At last, it therefore suggests appropriate ground pressure control measures as strengthening observation of ground pressure and adopting false slope for exploitation and strengthening support for reasonable push and slide based on the adverse ground pressure behaviors possibly occurring in the mining technique. This serves to gather data and lay sturdy founda-tion for further probe into the mining technique, and offers theoretical and technical grounds for concrete implementation of the mining technique.

  2. Research on the Reasonable Spacing of Holes in Gas Drainage along Coal Seams in Consideration of the Superimposed Effect of Drainage

    Directory of Open Access Journals (Sweden)

    Li Bo

    2016-02-01

    Full Text Available o determine the reasonable spacing of holes for gas drainage, an experimental study was conducted on the effective influence radius of drilling hole through the pressure drop method based on the actual condition of coal seams. The coal seam that contains gas is regarded as elastic-plastic dual media. The governing equation of gas transport is established by analyzing the different flow forms of gas in the pore and fissure systems as well as by considering the mass exchange capacity in the pore-fissure system. The equation is embedded into COMSOL Multiphysics (COMSOL software to simulate the gas drainage effect further by drilling along a coal seam under a 3-D space. Upon confirming the effective radius and drainage influence radius of a single pore, the holes for gas drainage can be reasonably spaced along the coal seam by analyzing the change features of coal permeability around the borehole and the functional mechanism of the superimposed effect of drainage, namely, 2r≤L≤R. The study results can reliably guide practical gas drainage theoretically and can also effectively lower the cost of gas drainage as well as ensure the safe production in mines.

  3. Model of coupled gas flow and deformation process in heterogeneous coal seams and its application

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-hui; ZHAO Quan-sheng; YU Yong-jiang

    2011-01-01

    The heterogeneity of coal was studied by mechanical tests. Probability plots of experimental data show that the mechanical parameters of heterogeneous coal follow a Weibull distribution. Based on elasto-plastic mechanics and gas dynamics, the model of coupled gas flow and deformation process of heterogeneous coal was presented and the effects of heterogeneity of coal on gas flow and failure of coal were investigated. Major findings include: The effect of the heterogeneity of coal on gas flow and mechanical failure of coal can be considered by the model in this paper. Failure of coal has a great effect on gas flow.

  4. The Outburst Risk as a Function of the Methane Capacity and Firmness of a Coal Seam

    Science.gov (United States)

    Wierzbicki, Mirosław; Skoczylas, Norbert

    2014-12-01

    In most coal basins that are currently being exploited, gas and rock outbursts pose a considerable safety threat. The risk of their occurrence is frequently assessed by means of a parameter known as the methane capacity of coal. In a lot of countries, the evaluation of the mechanical properties of coal is conducted by means of another parameter: the firmness of coal. Due to the laboratory investigations and in situ observations carried out by the authors of this paper, it was possible to determine a function space in which the outburst risk can be described as a function of the methane capacity and firmness of a coal seam. This, in turn, made it possible to link the "gas factor" to the "mechanical factor", and thus provide a more comprehensive risk analysis. Wyrzuty gazów i skał stanowią duże zagrożenie w większości obecnie eksploatowanych zagłębi węglowych. Bardzo często wykorzystywanym parametrem oceny stanu zagrożenia wyrzutowego jest zawartość metanu w węglu. W wielu krajach do oceny mechanicznych parametrów węgla wykorzystuje się zwięzłość. Autorzy przeprowadzili badania laboratoryjne polegające na prowokacjach wyrzutów w skali laboratoryjnej. Jako materiał badawczy wykorzystane zostały brykiety węglowe. W trakcie badań wstępnych ustalona została zależność pomiędzy porowatością brykietów, a ich zwięzłością f oraz pomiędzy ciśnieniem nasycania metanem, a wskaźnikiem intensywności desorpcji dP. Pozwoliło to na przygotowywanie eksperymentów o kontrolowanych parametrach gazowych (wskaźnik intensywności desorpcji) oraz wytrzymałościowych (zwięzłość). Opracowana została metoda kontrolowania intensywności prowokacji wyrzutu poprzez określenie tempa spadku ciśnienia gazu przed czołem brykietu. Dzięki temu dla siatki parametrów f-dP możliwe było poszukiwanie minimalnej, skutecznej intensywności prowokacji wyrzutu. Znormalizowana wartość stałej czasowej spadku ciśnienia przed czołem brykietu powoduj

  5. 含构造煤煤层的AVA响应特性分析%Analysis on AVA corresponding of coal seams contain tectonic coals

    Institute of Scientific and Technical Information of China (English)

    程龙

    2015-01-01

    The outburst of gas and CBM mining are seriously inlfuenced by the distribution and thickness of tectonic coals in coal seams. The paper obtained the seismic recordings with the incidence angle from 0 to 35 °by forward modeling the different distribution and thickness of tectonic coals in coal seams, and the AVA corresponding of both cases were analyzed. The Gaussian White noise with different SnR was added to the seismic recordings, for discussing the characteristics of AVA corresponding inlfuenced by the SNR of recordings. And we realized that the AVA corresponding was serious affected when the SnR was less than 2. Though the above analysis, we believe this study can guide the exploration of tectonic coals.%煤层中构造煤的分布位置和厚度对瓦斯突出和煤层气开采影响较大。本文通过建立构造煤在煤层中的不同分布位置和厚度模型,褶积得到入射角为0-35°的地震记录,并分析两种情况下的煤层AVA响应特性。考虑到资料信噪比对煤层AVA响应的影响,在褶积记录中加入不同信噪比的高斯白噪声进行分析,认为当资料信噪比低于2时,含构造煤煤层的AVA响应特性受影响较大。通过以上分析,本研究可用于指导地震勘探中的构造煤解释。

  6. Modelling of a coal seam of the deposit Đurđevik (BiH) by means of 2D reflection seismic imaging

    Science.gov (United States)

    Arsenović, Siniša; Urošević, Milovan; Sretenović, Branislav; Cvetkov, Vesna; Životić, Dragana

    2016-06-01

    A low cost 2D reflection seismic survey was used to map the continuity of the main seams as well as the numerous faults at the Đurđevik sub-bituminous coal deposit (BiH). A 24-channel seismic data acquisition system was available for this survey. The natural high reflectivity of the coal seams and a favourable geometry of seismic profiles enabled the identification and correlation of major faults across the area. Rugged terrain presented challenges to both data acquisition and processing. Stacks of acceptable quality were obtained only after the application of surface consistent statics and careful application of multi-channel filtering. A set of recorded 2D lines was interpreted in a 3D environment. Inferred structural elements disrupting the seam continuity were identified and were in agreement with available drilling results and mine workings. The result of this work was used to reduce mining hazards and also to help optimise mine planning.

  7. Mechanism of the rib spalling and the controlling in the very soft coal seam

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jia-chen [China University of Mining and Technology, Beijing (China). Laboratory of Coal Resources and Mine Safety Technology

    2007-08-15

    The mechanism of rib spalling was studied and a way of controlling it was proposed by decreasing coal wall pressure and increasing the shear strength of the coal wall. Using the top coal caving technique and increasing the resistance of the support can reduce the pressure on the coal wall. The cohesion and shear strength of the coal wall may be increased by means of water infusion through the coal wall. These are effective ways of preventing rib spalling. The quick advance of the coal wall and having the correct low wall height are also advantageous to wall stability. 2 refs., 11 figs.

  8. JV Task 109 - Risk Assessment and Feasibility of Remedial Alternatives for Coal Seam at Garrison, North Dakota

    Energy Technology Data Exchange (ETDEWEB)

    Jarda Solc

    2008-01-01

    The Energy & Environmental Research Center (EERC) conducted an evaluation of alternative technologies for remediation of hydrocarbon-contaminated coal seam, including impacted soils and groundwater in Garrison, North Dakota. Geotechnical characteristics of the impacted fractured coal seam provide for rapid off-site contaminant transport, with the currently identified impacted zone covering an area of about 40 acres. Regardless of the exposure mechanism (free, dissolved, or vapor phase), results of laboratory tests confirmed secondary release of gasoline-based compounds from contaminated coal to water reaching concentrations documented from the impacted areas. Coal laboratory tests confirmed low risks associated with spontaneous ignition of gasoline-contaminated coal. High contaminant recovery efficiency for the vacuum-enhanced recovery pilot tests conducted at three selected locations confirmed its feasibility for full-scale remediation. A total of 3500 gallons (13.3 m{sup 3}) of contaminated groundwater and over 430,000 ft{sup 3} (12,200 m{sup 3}) of soil vapor were extracted during vacuum-enhanced recovery testing conducted July 17-24, 2007, resulting in the removal of about 1330 lb (603 kg) of hydrocarbons, an equivalent of about 213 gallons of product. The summary of project activities is as follows: (1) Groundwater and vapor monitoring for existing wells, including domestic wells, conducted on a monthly basis from December 12, 2006, to June 6, 2007. This monitoring activity conducted prior to initiation of the EERC field investigation was requested by NDDH in a letter dated December 1, 2006. (2) Drilling of 20 soil borings, including installation of extraction and monitoring wells conducted April 30-May 4 and May 14-18, 2007. (3) Groundwater sampling and water-table monitoring conducted June 11-13, 2007. (4) Evaluation of the feasibility of using a camera survey for delineation of mining voids conducted May 16 and September 10-11, 2007. (5) Survey of all wells

  9. Comparative analysis for performance of brown coal combustion in a vortex furnace with improved design

    Science.gov (United States)

    Krasinsky, D. V.

    2016-09-01

    Comparative study of 3D numerical simulation of fluid flow and coal-firing processes was applied for flame combustion of Kansk-Achinsk brown coal in a vortex furnace of improved design with bottom injection of secondary air. The analysis of engineering performance of this furnace was carried out for several operational modes as a function of coal grinding fineness and coal input rate. The preferable operational regime for furnace was found.

  10. New interpretations of the facies of the Rhenish brown coal of West Germany

    Energy Technology Data Exchange (ETDEWEB)

    Hagemann, H.W.; Wolf, M.

    1987-05-01

    New ideas concerning the understanding of the facies of the Rhenish brown coal of West Germany are discussed. These new interpretations are based on a significantly larger number of samples and refined procedures for analysis within the field of paleobotany, palynology, coal petrology and organic geochemistry than were available to P.W. Thomson and M. Teichmuller. The light and dark bands in the coal are mainly the result of different degrees of plant decomposition. The influence of the peat-forming plant communities plays a subordinate role in the petrographical composition of these particular strata of the Rhenish brown coal. 28 refs.

  11. The prospects of hard and brown coal in Poland and in the European Union

    Energy Technology Data Exchange (ETDEWEB)

    Gawlik, Lidia; Majchrzak, Henryk; Mokrzycki, Eugeniusz; Uliasz-Bochenczyk, Alicja

    2010-09-15

    Poland possess significant reserves of hard and brown coal and is an important producer of these fuels, for that reason coal has a dominant position in Polish energy balance. The government document describing energy policy of Poland up to the year 2030 treats Polish coal as an stabilizer of national energy safety. The progress in clean coal technologies development is a key element to determine the role of Polish coal both in Polish and EU economy. The possibilities of prospective use of coal pointing at the main direction of clean technology development has also been discussed in the paper.

  12. Differentiation of impregnation by non-impregnation of high volatile coal seams; Differenzierung der Anwendung der Traenkarbeit durch Traenkverzicht in fuer die Traenkung ungeeigneten Floezpartien

    Energy Technology Data Exchange (ETDEWEB)

    Henke, B. [Deutsche Montan Technologie GmbH, Essen (Germany). Gas and Fire Div.

    2004-07-01

    Water infusion into coal seams before winning is a measure as well for dust control as for fire and explosion prevention. The efficiency of water infusion in low volatile coal is much better as in high volatile coal. Highly efficient follow up dust control technologies in plough and shearer faces meanwhile let vanish the effect of water infusion in high volatile coal. So far water infusion no more is necessary in such seams. Underground trials have shown, that the effect of water infusion cannot be recognized any more, if highly efficient follow up dust control techniques are used. In present time water infusion in high volatile coal seams can be dropped, so far the limitations concerning low dust levels, set up by the mining authority, will be matched. By using further developed lab trials for testing coal samples on their behaviour concerning water infusion individual seams or even coal faces can be assessed concerning dropping water infusion. (orig.) [German] Das Traenken der Kohle vor der Gewinnung ist eine Massnahme zur Staubreduzierung sowohl aus der Sicht des Gesundheitsschutzes als auch des Brand- und Explosionsschutzes. Die Effektivitaet des Traenkens ist in hoch inkohlten Floezpartien jedoch hoeher als in niedrig inkohlten Floezpartien. Die hochwirksamen Staubbekaempfungsmassnahmen im Bereich der schneidenden und schaelenden Gewinnung lassen inzwischen den Traenkeffekt in den Hintergrund treten, so dass die Moeglichkeit gegeben ist, auf diese Massnahme in niedrig inkohlten Floezpartien zu verzichten. In Betriebsversuchen konnte nachgewiesen werden, dass die Wirksamkeit der Traenkung nicht mehr nachweisbar ist, wenn optimierte sekundaere Staubbekaempfungstechniken eingesetzt werden. Heute kann in stratigraphisch jungen Floezen bei der Gewinnung auf Traenkbarkeit verzichtet werden, wenn die Einhaltung bergbehoerdlicher Auflagen zur Sicherstellung der niedrigeren Staubbelastung gewaehrleistet ist. Die Weiterentwicklung der vorgeschalteten Laborversuche zur

  13. Estimating Effective Seismic Anisotropy Of Coal Seam Gas Reservoirs from Sonic Log Data Using Orthorhombic Buckus-style Upscaling

    Science.gov (United States)

    Gross, Lutz; Tyson, Stephen

    2015-04-01

    Fracture density and orientation are key parameters controlling productivity of coal seam gas reservoirs. Seismic anisotropy can help to identify and quantify fracture characteristics. In particular, wide offset and dense azimuthal coverage land seismic recordings offers the opportunity for recovery of anisotropy parameters. In many coal seam gas reservoirs (eg. Walloon Subgroup in the Surat Basin, Queensland, Australia (Esterle et al. 2013)) the thickness of coal-beds and interbeds (e.g mud-stone) are well below the seismic wave length (0.3-1m versus 5-15m). In these situations, the observed seismic anisotropy parameters represent effective elastic properties of the composite media formed of fractured, anisotropic coal and isotropic interbed. As a consequence observed seismic anisotropy cannot directly be linked to fracture characteristics but requires a more careful interpretation. In the paper we will discuss techniques to estimate effective seismic anisotropy parameters from well log data with the objective to improve the interpretation for the case of layered thin coal beds. In the first step we use sonic log data to reconstruct the elasticity parameters as function of depth (at the resolution of the sonic log). It is assumed that within a sample fractures are sparse, of the same size and orientation, penny-shaped and equally spaced. Following classical fracture model this can be modeled as an elastic horizontally transversely isotropic (HTI) media (Schoenberg & Sayers 1995). Under the additional assumption of dry fractures, normal and tangential fracture weakness is estimated from slow and fast shear wave velocities of the sonic log. In the second step we apply Backus-style upscaling to construct effective anisotropy parameters on an appropriate length scale. In order to honor the HTI anisotropy present at each layer we have developed a new extension of the classical Backus averaging for layered isotropic media (Backus 1962) . Our new method assumes layered

  14. Characteristics and stability of slope movement response to underground mining of shallow coal seams away from gullies

    Institute of Scientific and Technical Information of China (English)

    Zhang Dongsheng; Fan Gangwei; Wang Xufeng

    2012-01-01

    Underground pressure is abnormal during mining of shallow coal seams under gullies.We studied gully slope movements,subject to underground mining,with physical simulation and theoretical analysis.The rules disclose that the slope rock slides horizontally in response to mining in the direction of gullies and rotates reversely with the appearance of a polygon block in mining away from gullies.We focused our attention on the case of mining away from a gully.We built a mechanical model in terms of a polygon block hinged structure and investigated the variation of horizontal thrust and shear force at the hinged point in relation to the rotation angle under different fragmentations.The Sliding-Rotation instability conditions of the polygon block hinged structure are presented based on the analyses of sliding instability and rotation instability.These results can serve as a theoretical guide for roof control during mining away from gullies in a coalfield defined by gullies.

  15. Enhanced recovery of unconventional gas. Volume II. The program. [Tight gas basins; Devonian shale; coal seams; geopressured aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Kuuskraa, V.A.; Brashear, J.P.; Doscher, T.M.; Elkins, L.E.

    1978-10-01

    This study was conducted to assist public decision-makers in selecting among many choices to obtain new gas supplies by addressing 2 questions: 1) how severe is the need for additional future supplies of natural gas, and what is the economic potential of providing part of future supply through enhanced recovery from unconventional natural gas resources. The study also serves to assist the DOE in designing a cost-effective R and D program to stimulate industry to recover this unconventional gas and to produce it sooner. Tight gas basins, Devonian shale, methane from coal seams, and methane from geopressured aquifers are considered. It is concluded that unconventional sources, already providing about 1 Tcf per year, could provide from 3 to 4 Tcf in 1985 and from 6 to 8 Tcf in 1990 (at $1.75 and $3.00 per Mcf, respectively). However, even with these additions to supply, gas supply is projected to remain below 1977 usage levels. (DLC)

  16. Early Eocene carbon isotope excursions: Evidence from the terrestrial coal seam in the Fushun Basin, Northeast China

    Science.gov (United States)

    Chen, Zuoling; Ding, Zhongli; Tang, Zihua; Wang, Xu; Yang, Shiling

    2014-05-01

    A series of transient global warming events between 56 and 50 Ma are characterized by a pronounced negative carbon isotope excursion (CIE). However, the documents of these hyperthermals, such as Eocene Thermal Maximum 2 and H2 events, have come chiefly from marine sediments, and their expression in terrestrial organic carbon is still poorly constrained. Here we yield a high-resolution carbon isotope record of terrestrial organic material from the Fushun Basin, which displays four prominent CIEs with magnitudes larger than 2.5‰. Based on age constraint and comparisons with deep-sea records, our data provide the first evidence of the four hyperthermals in coal seams and suggest a global significance of these events. Moreover, the difference of CIE magnitudes between marine and terrestrial records shows a significant linear correlation with the marine carbonate CIE, implying that these events are likely attributable to recurring injections of 13C-depleted carbon from submarine methane hydrates and/or permafrost.

  17. Water inrush evaluation of coal seam floor by integrating the water inrush coefficient and the information of water abundance

    Institute of Scientific and Technical Information of China (English)

    Shi Longqing; Qiu Mei; Wei Wenxue; Xu Dongjing; Han Jin

    2014-01-01

    The method of singular coefficient of water inrush to achieve safety mining has limitation and one sidedness. Aiming at the problem above, large amounts of data about water inrush were collected. Then the data, including the maximum water inrush, water inrush coefficient and water abundance in aquifers of working face, were processed by the statistical analysis. The analysis results indicate that both water inrush coefficient and water abundance in aquifers should be taken into consideration when evaluating the danger of water inrush from coal seam floor. The prediction model of safe-mining evaluation grade was built by using the support vector machine, and the result shows that this model has high classifica-tion accuracy. A feasible classification system of water-inrush safety evaluation can be got by using the data visualization method which makes the implicit support vector machine models explicit.

  18. Co-pyrolysis of a Ukrainian low-grade coal (brown) with plastics

    Energy Technology Data Exchange (ETDEWEB)

    V.N. Shevkoplyas [National Academy of Sciences of Ukraine, Donetsk (Ukraine)

    2003-07-01

    An effective pathway of the wastes plastics utilization can be its co-pyrolysis with a low-grade (brown) coal. The Dneprovsky deposit brown coal (Ukraine) and waste plastics as a polyethyleneterephthalate in this investigation were taken. The brown coal-plastics mixed used: 19:1; 9:1 and 4:1 ratio that was as 5, 10 and 20 % plastics additive to the brown coal. The co-pyrolysis mix prepared in the temperature region 450-800{sup o}C in a fixed bed reactor has been carried out. The process time was 0, 60 and 120 min., heating rate - 25{sup o}C/min. The influence plastics additive on the co-pyrolysis yield has been estimated. The influence of the co-pyrolysis isothermal time on the yield and properties of the tars produced has been studied. The mass balances of co-pyrolysis brown coal with plastics have been calculated. It was concluded that the co-pyrolysis brown coal with plastics is a way to utilize organic pollutants. 3 refs., 1 fig., 6 tabs.

  19. Underground Coal Mine Methane Displacement by Injecting Low-pressure Gas into the Meta-anthracite Seam: Laboratory and Field Tests

    Directory of Open Access Journals (Sweden)

    Yu Hong

    2014-09-01

    Full Text Available Because of the strong adsorption capacity of meta-anthracite, the gas content of a meta-anthracite seam can be as high as 10 m3/t, with a gas pressure lower than 0.74 MPa; this results in low efficiency of gas extraction in underground mines. To enhance low-pressure methane extraction efficiency in meta-anthracite seams, a new approach – methane displacement by gas injection – has been developed, investigated in the laboratory, and then applied in the field in the Fuyanshan coal mine. Laboratory results show that when the gas content of the coal seam is high, methane displacement by nitrogen injection is difficult. The volume of methane displaced is directly related to the pressure difference between the coal seam gas pressure and the injection gas pressure. If the total gas pressure is greater than 0.5 MPa after nitrogen injection, then the methane displacement efficiency will be greatly enhanced. It is also confirmed that the displacement efficiency can be improved by injecting inert gas to change the partial pressure of the methane. Field test data show quite good methane displacement efficiency.

  20. Control Mechanism of Rock Burst in the Floor of Roadway Driven along Next Goaf in Thick Coal Seam with Large Obliquity Angle in Deep Well

    Directory of Open Access Journals (Sweden)

    Yunhai Cheng

    2015-01-01

    Full Text Available This paper deals with the theoretical aspects combined with stress analysis over the floor strata of coal seam and the calculation model for the stress on the coal floor. Basically, this research presents the relevant results obtained for the rock burst prevention in the floor of roadway driven along next goaf in the exploitation of thick coal seam with large obliquity in deep well and rock burst tendency. The control mechanism of rock burst in the roadway driven along next goaf is revealed in the present work. That is, the danger of rock burst can be removed by changing the stress environment for the energy accumulation of the floor and by reducing the impact on the roadway floor from the strong dynamic pressure. This result can be profitable being used at the design stage of appropriate position of roadway undergoing rock burst tendency in similar conditions. Based on the analysis regarding the control mechanism, this paper presents a novel approach to the prevention of rock burst in roadway floor under the above conditions. That is, the return airway is placed within the goaf of the upper working face that can prevent the rock burst effectively. And in this way, mining without coal pillar in the thick coal seam with large obliquity and large burial depth (over a thousand meters is realized. Practice also proves that the rock burst in the floor of roadway driven along next goaf is controlled and solved.

  1. Effects of caving-mining ratio on the coal and waste rocks gangue flows and the amount of cyclically caved coal in fully mechanized mining of super-thick coal seams

    Institute of Scientific and Technical Information of China (English)

    Zhang Ningbo; Liu Changyou; Pei Mengsong

    2015-01-01

    Aimed at determining the appropriate caving–mining ratio for fully mechanized mining of 20 m thick coal seam, this research investigated the effects of caving–mining ratio on the flow fields of coal and waste rocks, amount of cyclically caved coal and top coal loss by means of numerical modeling. The research was based on the geological conditions of panel 8102 in Tashan coal mine. The results indicated the loose coal and waste rocks formed an elliptical zone around the drawpoint. The ellipse enlarged with decreasing caving–mining ratio. And its long axis inclined to the gob gradually became vertical and facil-itating the caving and recovery of top coal. The top coal loss showed a cyclical variation;and the loss cycle was shortened with the decreasing in caving–mining ratio. Moreover, the mean squared error (MSE) of the amount of cyclically caved coal went up with increasing caving–mining ratio, indicating a growing imbalance of amount of cyclically caved coal, which could impede the coordinated mining and caving operations. Finally it was found that a caving–mining ratio of 1:2.51 should be reasonable for the conditions.

  2. Masson ditch coal seam gas occurrence characteristics%马尾沟矿井9#煤层瓦斯赋存特征研究

    Institute of Scientific and Technical Information of China (English)

    贾猛; 谭志宏

    2012-01-01

    As everyone knows, although the state of the coal mine safety management attaches great importance to, and put a lot oi manpower and material resources, but, as a worldwide problem, coal mine safety situation is still grim. Mining depth, mining conditions are becoming more and more complex, coal-bed gas is more difficult to manage, use gas geology theory, combined with cauda equina ditch mine information, research and analysis of the Masson ditch mine gas occurrence conditions of coal mine, geological structure characteristics, find out the influ ence of mine gas in the main control factors of coal seam buried depth is. Establishment of coal seam gas content in coal seam floor elevation and mathematical correlation relationship, prediction of deep coal seam gas occurrence regularity, thus for the safe production in mine and coal seam in deep mining has important significance.%众所周知,尽管国家对煤矿安全治理极其重视,并投入了大量的人力物力,但是,作为一个世界性难题,煤矿安全形势依然严峻。开采深度加深,开采条件就越来越复杂,煤层瓦斯更加难以治理,运用瓦斯地质理论,结合马尾沟矿井相关资料,研究分析了马尾沟矿井瓦斯赋存条件,探讨矿井地质构造特征,找出影响矿井瓦斯赋存的主控因素是煤层埋藏深度。建立煤层底板标高和煤层瓦斯含量的数学相关性关系,预测出深部煤层瓦斯赋存规律,从而对矿井安全生产以及煤层深部开采都有重要意义。

  3. Influence of additives on the increase of the heating value of Bayah's coal with upgrading brown coal (UBC) method

    Science.gov (United States)

    Heriyanto, Heri; Widya Ernayati, K.; Umam, Chairul; Margareta, Nita

    2015-12-01

    UBC (upgrading brown coal) is a method of improving the quality of coal by using oil as an additive. Through processing in the oil media, not just the calories that increase, but there is also water repellent properties and a decrease in the tendency of spontaneous combustion of coal products produced. The results showed a decrease in the water levels of natural coal bayah reached 69%, increase in calorific value reached 21.2%. Increased caloric value and reduced water content caused by the water molecules on replacing seal the pores of coal by oil and atoms C on the oil that is bound to increase the percentage of coal carbon. As a result of this experiment is, the produced coal has better calorific value, the increasing of this new calorific value up to 23.8% with the additive waste lubricant, and the moisture content reduced up to 69.45%.

  4. 阿富汗科里奇-阿什普什塔勘查区煤层煤质特征研究%A Study on Coal Seam and Coal Quality Characteristics in Coryqi-Ashepashoonta Perambulation Area, Afghanistan

    Institute of Scientific and Technical Information of China (English)

    王佟; 彭正奇

    2012-01-01

    阿富汗科里奇-阿什普什塔勘查区面积约69.098km2,含煤地层为侏罗系中统和下统.侏罗系中统下段阿什普塔组含一层可采煤层,即7煤层.侏罗系下统科里奇组下段含可采煤4层,分别为4、2上、2、2下煤层,其中2煤层为西部主要可采煤层,总资源量11 389.6万t.7煤层煤质为低灰、特低硫、特低磷、中热值、中等软化温度灰之不粘煤;其他煤层均为中-高灰、低硫、低磷、中热值、高挥发份、中等软化温度灰之长焰煤.%The Coryqi-Ashepashoonta perambulation area, Afghanistan has an area of about 69.098km2; its coal-bearing strata belong to Middle Series and Lower Series of Jurassic System. The Lower Member Ashepashoonta Formation of Middle Series has 1 mineable coal seam, namely No.7 coal seam; while Lower Series Coryqi Formation has 4 mineable coal seams, namely Nos.4, 2U, 2 and 2L coal seams, in which, the No.2 coal seam is the main mineable coal seam in the western part, with total resources of 113.896 million tons. The coal quality of No.7 coal is low ash, extra low sulfur and phosphorus, medium calorific value, medium softening temperature non-caking coal; while others are medium-high ash, low sulfur and phosphorus, medium calorific value, high volatile matter, medium softening temperature long flame coal.

  5. Capital investment at North Bohemian Brown Coal Mines

    Energy Technology Data Exchange (ETDEWEB)

    Vavrecka, S.

    1987-03-01

    Various categories of investment are discussed to be undertaken by North Bohemian Brown Coal Mines: State Plan projects, such as new extraction capacity at Most and Vrsany mines; other construction work, such as schools and recreation facilities, housing construction; underground mine workings; equipment and machinery not included in other categories; restoration work, such as the Ervenicky road/rail/water corridor; work to remove obstacles hindering future mining operations. Investments are briefly summarizes since the beginning of the 5th Five Year Plan as being concerned mainly with the shift in emphasis from underground mining to surface mining at 8 large-scale mines (Merkur, Brezno, Vrsany, Sverma, VCSA, Most, VMG, Chabrovice). An analysis of investment procedures conducted in 1980 is briefly discussed, the results of which had 4 main themes: investment control systems should be strengthened, communications between general directorate and individual departments should be improved, links between specialist institutes should be improved and these recommendations should be built into the organizational structure.

  6. Effects of pretreatment in steam on the pyrolysis behavior of Loy Yang brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Cai Zeng; George Favas; Hongwei Wu; Alan L. Chaffee; Jun-ichiro Hayashi; Chun-Zhu Li [Monash University, Vic. (Australia). CRC for Clean Power from Lignite, Department of Chemical Engineering

    2006-02-01

    Dewatering/drying of Victorian brown coal will be an integral part of future brown coal utilization processes aimed at the reduction of greenhouse gas emissions. This study aims to investigate the effects of the thermal pretreatment of brown coal in the presence of steam/water on its subsequent pyrolysis behavior. A Victorian (Loy Yang) brown coal was thermally pretreated in pressurized steam and inert atmospheres. The pyrolysis behavior of these pretreated coal samples was investigated in a wire-mesh reactor. While the pretreatment in steam at temperatures higher than 250{sup o}C increased the char yield of the steam-treated coal, it did not affect the overall pyrolysis char yield at 1000{sup o} C s{sup -1} if the weight loss during the pretreatment in steam was also considered. However, the tar yield decreased significantly after the pretreatment in the presence of steam. The UV-fluorescence spectroscopy of tars revealed that the release of large aromatic systems from the steam-treated coal was only affected by the pretreatment in steam if the treatment temperature was very high (e.g. 350{sup o}C). The loss of NaCl and the use of high pressure during the pretreatment of brown coal in steam were not the main reasons for the changes in the observed tar yield. The hydrolysis of O-containing structures such as ethers, esters, and carboxylates during the pretreatment in the presence of steam plays an important role in the fates of these O-containing structures during pretreatment and subsequent pyrolysis, leading to changes in the pyrolysis behavior of the brown coal. 36 refs., 8 figs.

  7. The application of GIS in predicting water gushing from sixth coal seam floor in Liuqiao No. 2 coal mine

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M.; Li, D. [Huainan Mining Institute (China)

    1997-12-31

    Based on the detailed introduction of the method and procedure of GIS in the prediction of coal floor water influx, the paper establishes a multi-factor water gushing model, predicts water influx divisions taking Liuqiao No. 2 coal mine in North-Anhui as an example. A good result is obtained, and a new way of forecasting water influx from coal floors is provided. 2 refs., 3 figs.

  8. Application of principal-component analysis to the interpretation of brown coal properties

    Energy Technology Data Exchange (ETDEWEB)

    Tesch, S.; Otto, M. [TU Bergakademie, Freiberg (Germany). Institute for Analytical Chemistry

    1995-07-01

    The characterization of coal properties using principal-component analysis is described. The aim is to obtain correlations between a large number of chemical and technological parameters as well as FT-i.r. spectroscopic data. A database on 44 brown coals from different deposits was interpreted. After computation of the principal components, scatterplots and component-weight plots are presented for the first two or three principal components. The overlap of the component-weights plot and the scatterplot (biplot) shows how it is possible to classify brown coals by means of selected characteristics. 14 refs., 6 figs., 1 tab.

  9. 穿层钻孔煤孔段造斜钻进技术研究%Directional Drilling for Bore Hole Interval Through Coal Seam

    Institute of Scientific and Technical Information of China (English)

    童碧; 孙新胜; 王力; 徐保龙; 贾明群; 石会田

    2013-01-01

    The paper introduces the borehole trajectory design and directional drilling technique for the coal seam for gas drainage.Directional drilling has been tested to make the bore hole path turn downward at the coal interval to extend the travelling length of the borehole in the coal seam;thus improving gas drainage efficiency.During drilling, the drilling string configuration of high build-rates was used to make the deflecting rate up to 2 °/m at maximum.Compared to conventional drilling technology, the borehole interval in the coal seam is extended 2.45 times.%介绍了抽放瓦斯穿层孔煤孔段造斜钻进的钻孔轨迹设计及钻进工艺,在试验中采用定向钻进技术,使穿层钻孔轨迹在煤孔段产生向下弯曲,延长了煤孔段长度,提高瓦斯抽放效率。施工中使用强造斜组合钻具钻进,使钻孔最大造斜强度达到2°/m,相对于常规钻进工艺,煤孔段最大延长2.45倍。

  10. Co-pyrolysis of hydrothermally upgraded brown coal and wax prepared from waste plastics

    Energy Technology Data Exchange (ETDEWEB)

    Kouichi Miura; Susan A. Roces; Monthicha Pattatapanusak; Hiroyuki Nakagawa; Ryuichi Ashida; Masato Morimoto [Kyoto University, Kyoto (Japan). Department of Chemical Engineering

    2007-07-01

    We have recently presented a hydrothermal extraction method that not only removes water from brown coal but also upgrades the coal and extracts low molecular mass compounds simultaneously. The upgraded coal contained much less oxygen than the raw coal. However, it still needs to be further upgraded to be utilized as a substitute for bituminous coal. In this study co-pyrolysis of the upgraded coals and waxes formed from waste plastics was investigated for this purpose. Waxes were prepared through pyrolysis of polyethylene, polypropylene, and polyethylene terephtalate. Upgraded coals were then impregnated with the waxes in an autoclave at 200{sup o}C under pressure. The mixtures of coal and wax were rapidly heated up to 1040{sup o}C at about 3000{sup o}C/s using a Curie point pyrolyzer in an inert atmosphere. The char yield was greatly enhanced by a factor of 1.1 to 1.3 compared to the char yield obtained when the upgraded coals and waxes were pyrolyzed independently. Even under a slower heating rate (0.17{sup o}C/s) the char yields increased by a factor of 1.2 for the all mixtures of the upgraded coal and waxes. Since no such effect was found when the raw brown coal was impregnated with waxes, it was suggested that the modification of the structure of brown coal by the hydrothermal extraction could enhance interactions between the coal and the wax when co-pyrolyzed. Effect of wax mixing ratio on co-pyrolysis behavior was also examined. The char yield dramatically increased when the ratio exceeded about 0.3 g/g for the pyrolysis of both under slow and rapid heating rates. This trend coincided with that of the swelling ratio of the upgraded coal impregnated with wax, indicating that some physical change by wax-impregnation affected the co-pyrolysis behavior. 5 refs., 14 figs., 3 tabs.

  11. Pico-nano bubble column flotation using static mixer-venturi tube for Pittsburgh No. 8 coal seam

    Institute of Scientific and Technical Information of China (English)

    Peng Felicia F.; Yu Xiong

    2015-01-01

    The flotation process is a particle-hydrophobic surface-based separation technique. To improve the essential flotation steps of collision and attachment probabilities, and reduce the step of detachment probabilities between air bubbles and hydrophobic particles, a selectively designed cavitation venturi tube combined with a static mixer can be used to generate very high numbers of pico and nano bubbles in a flotation column. Fully embraced by those high numbers of tiny bubbles, hydrophobic particles readily attract the tiny bubbles to their surfaces. The results of column flotation of Pittsburgh No. 8 seam coal are obtained in a 5.08 cm ID and 162 cm height flotation column equipped with a static mixer and cavitation venturi tube, using kerosene as collector and MIBC as frother. Design of the experimental procedure is combined with a statistical two-stepwise analysis to determine the optimal operating conditions for maximum recovery at a specified grade. The effect of independent variables on the responses has been explained. Combustible material recovery of 85–90% at clean coal product of 10–11%ash is obtained from feed of 29.6%ash, with a much-reduced amount of frother and collector than that used in conventional column flotation. The column flotation process utilizing pico and nano bubbles can also be extended to the lower limit and upper limit of particle size ranges, minus 75 lm and 300–600 lm, respectively, for better recovery.

  12. Assessing Connectivity Between an Overlying Aquifer and a Coal Seam Gas Resource Using Methane Isotopes, Dissolved Organic Carbon and Tritium

    Science.gov (United States)

    Iverach, Charlotte P.; Cendón, Dioni I.; Hankin, Stuart I.; Lowry, David; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.; Baker, Andy; Kelly, Bryce F. J.

    2015-11-01

    Coal seam gas (CSG) production can have an impact on groundwater quality and quantity in adjacent or overlying aquifers. To assess this impact we need to determine the background groundwater chemistry and to map geological pathways of hydraulic connectivity between aquifers. In south-east Queensland (Qld), Australia, a globally important CSG exploration and production province, we mapped hydraulic connectivity between the Walloon Coal Measures (WCM, the target formation for gas production) and the overlying Condamine River Alluvial Aquifer (CRAA), using groundwater methane (CH4) concentration and isotopic composition (δ13C-CH4), groundwater tritium (3H) and dissolved organic carbon (DOC) concentration. A continuous mobile CH4 survey adjacent to CSG developments was used to determine the source signature of CH4 derived from the WCM. Trends in groundwater δ13C-CH4 versus CH4 concentration, in association with DOC concentration and 3H analysis, identify locations where CH4 in the groundwater of the CRAA most likely originates from the WCM. The methodology is widely applicable in unconventional gas development regions worldwide for providing an early indicator of geological pathways of hydraulic connectivity.

  13. 松软低透煤层群开采保护层工作面瓦斯综合治理技术%Comprehensive Gas Control Technology for Mining Protective Seam Face in Soft Coal Seams with Low Permeability

    Institute of Scientific and Technical Information of China (English)

    胡明; 张玉明; 雷洪波; 姚峰

    2014-01-01

    In order to solve the problem of gas emission during the extraction of the protective seam in Yuyang Coal Mine, comprehensive gas control measures such as “U+ tailing way drainage” ventilation, gas pre-drainage from the seam being mined by large-diameter deep holes, gas drainage by crossing hole in the floor and so on were taken. The result showed that the gas concentration in return air of the working face was controlled below 0. 7% during coal mining and the month coal output of the face raised by 50%. This thus solved the gas overrun problem in the protective seam working face, improved the drawing rate of the face and realized safe production of the mine.%为了解决渝阳煤矿突出矿井煤层群开采保护层工作面时瓦斯涌出的问题,采取了“U+尾排”通风、大直径深孔预抽本煤层瓦斯、底板穿层钻孔抽采瓦斯等综合治理措施,治理效果表明:回采期间工作面回风流中瓦斯体积分数控制在0.7%以下,工作面月产量提高了50%。解决了保护层工作面的瓦斯超限问题,同时提高了工作面的回采速度,实现了安全生产。

  14. Study on fasART neuro-fuzzy networks for distinguishing the difficulty degree of top coal caving in steep seam

    Institute of Scientific and Technical Information of China (English)

    FENG Tao; ZHAO Fu-jun; LIN Jian

    2005-01-01

    Distinguishing the difficulty degree of top coal caving was a precondition of the popularization and application of the roadway sub-level caving in steep seam. Because of complexity and uncertainty of the coal seam, the expression of influence factors was difficulty with exact data. According to the fuzzy and uncertainty of influence factors, triangular fuzzy membership functions were adopted to carry out the factors ambiguity, of which the factors not only have the consistency of semantic meaning, but also dissolve sufficiently expert knowledge. Based on the properties and structures of fasART fuzzy neural networks of fuzzy logic system and practical needs, a simplified fasART model was put forward, stability and reliability of the network were improved, the deficiency of learning sampies and uncertainty of the factors were better treated. The method is of effective and practical value was identified by experiments.

  15. Draft Genome Sequence of Cellulosilyticum sp. I15G10I2, a Novel Bacterium Isolated from a Coal Seam Gas Water Treatment Pond

    Science.gov (United States)

    Adelskov, Joseph

    2017-01-01

    ABSTRACT Cellulosilyticum sp. strain I15G10I2 was isolated from a coal seam gas water treatment pond at the Spring Gully water treatment facility, Roma, Queensland, Australia. Analysis of the genome of 4,489,861 bp and G+C content of 35.23% revealed that strain I15G10I2 shared limited similarity to members of the genus Cellulosilyticum, family Lachnospiraceae. PMID:28209824

  16. Novel pre-treatment of zeolite materials for the removal of sodium ions: potential materials for coal seam gas co-produced wastewater.

    Science.gov (United States)

    Santiago, Oscar; Walsh, Kerry; Kele, Ben; Gardner, Edward; Chapman, James

    2016-01-01

    Coal seam gas (CSG) is the extraction of methane gas that is desorbed from the coal seam and brought to the surface using a dewatering and depressurisation process within the saturated coalbed. The extracted water is often referred to as co-produced CSG water. In this study, co-produced water from the coal seam of the Bowen Basin (QLD, Australia) was characterised by high concentration levels of Na(+) (1156 mg/L), low concentrations of Ca(2+) (28.3 mg/L) and Mg(2+) (5.6 mg/L), high levels of salinity, which are expected to cause various environmental problems if released to land or waters. The potential treatment of co-produced water using locally sourced natural ion exchange (zeolite) material was assessed. The zeolite material was characterized for elemental composition and crystal structure. Natural, untreated zeolite demonstrated a capacity to adsorb Na(+) ions of 16.16 mEq/100 g, while a treated zeolite using NH4 (+) using a 1.0 M ammonium acetate (NH4C2H3O2) solution demonstrated an improved 136 % Na(+) capacity value of 38.28 mEq/100 g after 720 min of adsorption time. The theoretical exchange capacity of the natural zeolite was found to be 154 mEq/100 g. Reaction kinetics and diffusion models were used to determine the kinetic and diffusion parameters. Treated zeolite using a NH4 (+) pre-treatment represents an effective treatment to reduce Na(+) concentration in coal seam gas co-produced waters, supported by the measured and modelled kinetic rates and capacity.

  17. 浅埋煤层综采工作面设备选型与配套%Mining machine selection and matching for shallow coal seam

    Institute of Scientific and Technical Information of China (English)

    白如鸿; 王振华; 董康乾; 何鹏程

    2013-01-01

    The shallow coal seam of Shenfu mine area has characteristics of shallow buried depth,thin rock, overlying thick loose sand bed and severe mine pressure reveal, which requires more strict coal mine production safety. Through introduction and analysis of the shallow seam with special geological condition, this paper expounds the selection principle of the main mechanical equipment for shallow coal seam fully-mechanized, the theoretical calculation and related requirement of three machines assortment, then reasonably choose the form,type and technical features of three machines assortment. This paper have a realistic theoretical reference and guidance meaning for the equipment selection and matching work of the north Shaanxi shallow buried coal seam fully mechanized working face.%神府矿区浅埋煤层具有埋深浅、基岩薄、上覆厚松散沙层、矿压显现剧烈等特征,对于煤矿的安全生产提出了更严格的要求.本研究通过对浅埋煤层特殊赋予地质状况的介绍与分析,阐述了浅埋煤层综采工作面主要机械设备的选型原则、理论计算以及三机合理配套的相关要求,合理选择浅埋煤层综采工作面三机配套设备的形式、型号及技术特征.研究对于指导陕北浅埋煤层综采工作面设备选型与配套工作有现实的理论借鉴和指导意义.

  18. The Coal-Seq III Consortium. Advancing the Science of CO2 Sequestration in Coal Seam and Gas Shale Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Koperna, George [Advanced Resources International Inc., Arlington, VA (United States)

    2014-03-14

    The Coal-Seq consortium is a government-industry collaborative that was initially launched in 2000 as a U.S. Department of Energy sponsored investigation into CO2 sequestration in deep, unmineable coal seams. The consortium’s objective aimed to advancing industry’s understanding of complex coalbed methane and gas shale reservoir behavior in the presence of multi-component gases via laboratory experiments, theoretical model development and field validation studies. Research from this collaborative effort was utilized to produce modules to enhance reservoir simulation and modeling capabilities to assess the technical and economic potential for CO2 storage and enhanced coalbed methane recovery in coal basins. Coal-Seq Phase 3 expands upon the learnings garnered from Phase 1 & 2, which has led to further investigation into refined model development related to multicomponent equations-of-state, sorption and diffusion behavior, geomechanical and permeability studies, technical and economic feasibility studies for major international coal basins the extension of the work to gas shale reservoirs, and continued global technology exchange. The first research objective assesses changes in coal and shale properties with exposure to CO2 under field replicated conditions. Results indicate that no significant weakening occurs when coal and shale were exposed to CO2, therefore, there was no need to account for mechanical weakening of coal due to the injection of CO2 for modeling. The second major research objective evaluates cleat, Cp, and matrix, Cm, swelling/shrinkage compressibility under field replicated conditions. The experimental studies found that both Cp and Cm vary due to changes in reservoir pressure during injection and depletion under field replicated conditions. Using laboratory data from this study, a compressibility model was developed to predict the pore-volume compressibility, Cp, and the matrix compressibility, Cm, of coal and shale, which was applied to

  19. Comparison of Darcy`s Law and Fick`s Law of diffusion to determine the field parameters related to methane gas drainage in coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Basu, A.; Singh, R.N. [University of Wollongong, Wollongong, NSW (Australia). Dept. of Mechanical Engineering

    1994-09-01

    This paper describes the applications of two mathematical models and numerical methods to describe gas drainage in coal seams. The mechanisms of gas flow from coal are not very clear and can either follow Darcy`s Law or Fick`s Law of diffusion. At early stages where the gas pressure is high, Darcy`s law applies whereas at later stages when gas pressure is stabilised, Fick`s law of diffusion is applicable. Results for values of permeability are then compared to find correlation of these two methods. 8 refs., 11 figs., 1 tab.

  20. 保护层开采过程中煤岩损伤与瓦斯渗透性的变化研究%Research on the coal and rock damage and gas permeability in the protective seams mining

    Institute of Scientific and Technical Information of China (English)

    高峰; 许爱斌; 周福宝

    2011-01-01

    针对煤岩体损伤破坏特征,定义了煤岩体结构损伤变量,建立了相应的弹塑性损伤本构方程,并完成了有限元源程序的二次开发,利用此程序对乌兰煤矿双保护层开采实例进行了计算分析,给出了被保护层损伤程度和渗透性系数的变化规律,计算结果表明:7、8号煤层开采后,被保护2、3号煤层出现张拉损伤,煤层应力显著释放,煤岩体的渗透性急剧提高,有利于瓦斯运移和煤层瓦斯抽采,这与工程实际相吻合。%According to the damage characteristics of coal and rock,the damage variable of coal and rock structures was defined,the corresponding elastoplastic damage constitutive equation was established,and the secondary development of the finite element program was completed.The example of Wulan coal mine with double protective seam mining was calculated and analyzed by this new program,and the change laws of damage degree and permeability coefficient in protected coal seams were given.The results show that the tension damage appear in protected coal seams 2 and 3,the stress of coal seams are released clearly,and the permeability of coal seams quickly increases after the protective seams 7 and 8 mined.These results are beneficial for gas migration and extraction in coal seams,which is consistent with engineering practice.

  1. Rapid quality control for coal seams by gamma ray transmission technique

    CERN Document Server

    Raja-Sekhar, N; Nageswara-Rao, A S

    1999-01-01

    The quality of coal expressed as useful heat value (UHV) depends on various parameters such as fixed carbon, volatiles, ash and moisture. These factors have been assessed and the detailed dependence of UHV on these parameters has been studied for samples of coal from a local mine. The samples were subjected to collimated low energy gamma beams and correlation was obtained between the attenuation coefficient and UHV. The method is reliable, fast and non-destructive and can be used in the field for estimating UHV.

  2. Determination of indices and critical values of gas parameters of the first gas outburst in a coal seam of the Xieqiao Mine

    Institute of Scientific and Technical Information of China (English)

    Ou Jianchun; Liu Mingju; Zhang Chunru; Liu Yanwei; Wei Jianping

    2012-01-01

    Based on the important role in mine safety played by parameters of the first gas outburst,we propose a method of combining historic data,theoretical analysis and experimental research for the purpose of critical values of gas parameters of the first gas outburst in a coal seam of the Xieqiao Mine.According to a characteristic analysis and a summary of the rules ofcoal and gas outbursts in the No.8 coal seam ofa Huainan mine,we have investigated their effect on coal and gas outbursts in terms such as ground stress,gas,and coal structure.We have selected gas parameters and determined the critical values of each of the following indices:gas content as 7.7 m3/t,tectonic coal as 0.8 m thick,the absolute gas emission as 2 m3/min,the rate of change as 0.7 m3/min,the gas desorption index of a drilling chip K1 as 0.26 ml/(g min1/2) and the values of desorption indexes △h2 as 200 Pa.From a verification of the production,the results indicate that application of each index and their critical values significantly improve the level of safety in the production process,relieve the burden upon the mine,save much labor and bring clear economic benefits.

  3. Simulation research on the influence of eroded primary key strata on dynamic strata pressure of shallow coal seams in gully terrain

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhiqiang; Xu Jialin; Zhu Weibing; Shan Zhenjun

    2012-01-01

    In Huojitu Coal Mine of Shendong mining area,the dynamic strata pressure (DSP) accidents occurred when the working faces passed the gully terrain,Focusing on this problem,we used physical simulation experimental method to thoroughly study the influence of eroded overlying primary key strata (PKS) in the gully terrain on DSP of shallow coal seams in this paper.The result show that when mining activities took place in the uphill section of shallow coal seams in gully terrain and the PKS were eroded,the blocks could not form stable bond-beam structures since the horizontal force of PKS blocks in adjacent sloping surfaces were relatively small.The sliding instability of blocks caused rapid increase of the load on the sub-key strata (SKS) blocks,which resulted into coal slide and roof fall as well as sharp drop of active columns.This led to DSP phenomenon.When the PKS blocks were intact,there was no DSP phenomenon to enable blocks provide certain horizontal force to maintain stable bond-beam structure.The simulation results were verified by the mining practices of working face 21306 crossing the gully terrain in the Huojitu Coal Mine.

  4. Physicomechanical and some other properties of inter-coal seams (tonsteins) of the Donbas

    Energy Technology Data Exchange (ETDEWEB)

    Zaritskii, P.V.

    1981-01-01

    Characterized for the first time for the Donets basin in a large volume of material are the physicomechanical properties of tonsteins. Knowledge of these properties and the ability to determine some of them under field conditions facilitate the identification of tonsteins and their use in solving many practical problems of coal geology.

  5. On design for gas drainage of coal seam at 15th Seam at Shangshe Coal Company of Yangquan%阳泉上社煤炭公司15号煤层本煤层瓦斯抽放设计

    Institute of Scientific and Technical Information of China (English)

    武风元

    2012-01-01

    The paer introduces the gas drainage design at the coal seam of 15103 fully mechanized coal face of Shangshe Coal Mine in Yan- gquan, illustrates the design for the advanced deficient pumping holing and the drilling connection craft, sums up the safety operation points for the drainage of the coal seam, and proves by the practice that it has better gas drainage effect of the coal seam, so as to provide some precious experience for similar projects in future.%对阳泉上社煤矿15103综采工作面本煤层瓦斯抽放孔设计进行了介绍,分别阐述了预抽钻孔设计,钻孔连接工艺等内容,并总结出本煤层抽放的安全操作要点,经实践取得了良好的煤层瓦斯抽放效果,为今后类似工程提供了宝贵经验。

  6. Enrichment of radon and carbon dioxide in the open atmosphere of an Australian coal seam gas field.

    Science.gov (United States)

    Tait, Douglas R; Santos, Isaac R; Maher, Damien T; Cyronak, Tyler J; Davis, Rachael J

    2013-04-02

    Atmospheric radon ((222)Rn) and carbon dioxide (CO2) concentrations were used to gain insight into fugitive emissions in an Australian coal seam gas (CSG) field (Surat Basin, Tara region, Queensland). (222)Rn and CO2 concentrations were observed for 24 h within and outside the gas field. Both (222)Rn and CO2 concentrations followed a diurnal cycle with night time concentrations higher than day time concentrations. Average CO2 concentrations over the 24-h period ranged from ~390 ppm at the control site to ~467 ppm near the center of the gas field. A ~3 fold increase in maximum (222)Rn concentration was observed inside the gas field compared to outside of it. There was a significant relationship between maximum and average (222)Rn concentrations and the number of gas wells within a 3 km radius of the sampling sites (n = 5 stations; p radon relationship was a response to enhanced emissions within the gas field related to both point (well heads, pipelines, etc.) and diffuse soil sources. Radon may be useful in monitoring enhanced soil gas fluxes to the atmosphere due to changes in the geological structure associated with wells and hydraulic fracturing in CSG fields.

  7. Dissolved radon and uranium in groundwater in a potential coal seam gas development region (Richmond River Catchment, Australia).

    Science.gov (United States)

    Atkins, Marnie L; Santos, Isaac R; Perkins, Anita; Maher, Damien T

    2016-04-01

    The extraction of unconventional gas resources such as shale and coal seam gas (CSG) is rapidly expanding globally and often prevents the opportunity for comprehensive baseline groundwater investigations prior to drilling. Unconventional gas extraction often targets geological layers with high naturally occurring radioactive materials (NORM) and extraction practices may possibly mobilise radionuclides into regional and local drinking water resources. Here, we establish baseline groundwater radon and uranium levels in shallow aquifers overlying a potential CSG target formation in the Richmond River Catchment, Australia. A total of 91 groundwater samples from six different geological units showed highly variable radon activities (0.14-20.33 Bq/L) and uranium levels (0.001-2.77 μg/L) which were well below the Australian Drinking Water Guideline values (radon; 100 Bq/L and uranium; 17 μg/L). Therefore, from a radon and uranium perspective, the regional groundwater does not pose health risks to consumers. Uranium could not explain the distribution of radon in groundwater. Relatively high radon activities (7.88 ± 0.83 Bq/L) in the fractured Lismore Basalt aquifer coincided with very low uranium concentrations (0.04 ± 0.02 μg/L). In the Quaternary Sediments aquifers, a positive correlation between U and HCO3(-) (r(2) = 0.49, p groundwater investigations.

  8. Laser pyrolysis of brown coal in the field of low energies

    Energy Technology Data Exchange (ETDEWEB)

    Galkin, G.A.; Grigoriev, V.A.

    1981-01-01

    The authors studied thermal decomposition of Irsha-Borodinsky brown coal under pulse laser radiation within the energy density range from 2.5 to 25 J. cm /sub -2/ . It has been shown that the amount of the gas phase increases monotonously with the increase in the radiation energy density. Alongside the increase of the gas pressure, its composition changes noticeably. Maximum concentration of CH/sub 4/ and C/sub 2/H/sub 4/ is observed with the radiation energy density of 6.4J.cm /sup -2/ . Further increase in the radiation energy density leads to an abrupt increase in acetylene output. The assessment of the brown coal melting point under laser radiation by infrared spectra has been made. It has been shown that thermovacuum processing of a brown coal specimen contributes to a more complete carbonization of coal substance. Thermal processing of the specimen in the open air leads to a more profound thermodestruction of brown coal substance.

  9. Brown coal conversion by microwave plasma reactions under successive supply of methane

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, O.; Onoe, K.; Marushima, W.; Yamaguchi, T. [Chiba institute of Technology, Chiba (Japan). Dept. of Industrial Chemistry

    1998-10-01

    To develop an innovative method for directly converting brown coal to relatively important fuels and synthesis gases in a single step, while simultaneously upgrading the carbon content of the residue, microwave plasma technology was applied to the direct conversion of brown coal (Yallourn). Methane under reduced pressure was supplied through a quartz reactor into the irradiation zone and reacted with the coal bed placed downstream. Both the coal conversion and the carbon content of the residue were increased with an increase of irradiation time. The yield of oily products showed a maximum value (18 wt.%) at 2 min irradiation, and the fuels were composed mainly of aliphatic hydrocarbons in the range from C{sub 13} to C{sub 34}. Furthermore, carbon monoxide and hydrogen accompanied by a molar fraction of {lt} 16% of acetylene were mainly produced when the irradiation time was varied from 1 to 10 min. 4 refs., 5 figs., 1 tab.

  10. Research on Fire Prevention and Extinguishing of Fully Mechanized Top Coal Caving Face in High Gas and Inflammable Coal Seam%高瓦斯易燃煤层综放工作面的防灭火研究

    Institute of Scientific and Technical Information of China (English)

    昝平

    2014-01-01

    为了有效控制易自燃煤层放顶煤工作面自然发火,通过对煤自然发火机理的研究,以某矿8826放顶煤综采工作面为例,分析了低位放顶煤工作面采有三种防灭火技术进行防灭火的具体方案,优化出高效率、低投入、可操作性强的三相泡沫防灭火技术措施,以更好地防止煤层自燃,值得推广使用。%To effectively control the spontaneous combustion of top coal caving mining faces with spontaneous combustion coal seam,based on the research of the mechanism of coal spontaneous combustion,the coal spontaneous combustion is analyzed by taking 8826 fully mechanized top coal caving face of a coal mine as the example.The ad-vantages and disadvantages are discussed in implementation process of various fire-fighting technology of low caving working face,three-phase foam fire-fighting technical measures of high efficiency,low cost and strong operability are optimized,in order to better prevent the spontaneous combustion of coal seam.

  11. A Field Study on Simulation of CO2 Injection and ECBM Production and Prediction of CO2 Storage Capacity in Unmineable Coal Seam

    Directory of Open Access Journals (Sweden)

    Qin He

    2013-01-01

    Full Text Available CO2 sequestration into a coal seam project was studied and a numerical model was developed in this paper to simulate the primary and secondary coal bed methane production (CBM/ECBM and carbon dioxide (CO2 injection. The key geological and reservoir parameters, which are germane to driving enhanced coal bed methane (ECBM and CO2 sequestration processes, including cleat permeability, cleat porosity, CH4 adsorption time, CO2 adsorption time, CH4 Langmuir isotherm, CO2 Langmuir isotherm, and Palmer and Mansoori parameters, have been analyzed within a reasonable range. The model simulation results showed good matches for both CBM/ECBM production and CO2 injection compared with the field data. The history-matched model was used to estimate the total CO2 sequestration capacity in the field. The model forecast showed that the total CO2 injection capacity in the coal seam could be 22,817 tons, which is in agreement with the initial estimations based on the Langmuir isotherm experiment. Total CO2 injected in the first three years was 2,600 tons, which according to the model has increased methane recovery (due to ECBM by 6,700 scf/d.

  12. Research on the fully mechanized mechanization technology of the very thin coal seam with hard gangue%含硬夹矸极薄煤层综采机械化技术研究

    Institute of Scientific and Technical Information of China (English)

    葛家新; 位建峰; 王为东

    2015-01-01

    By the shearer renovation, Beisu Coal Mine improve the thin seam (especially containing iron sulfide concretions and hard inclusion of thin coal seam) comprehensive mechanized mining technology level, eliminate the safety hidden danger of blasting working face, greatly reduce the mining coal worker's labor intensity, and improve the working environment, which ifnd a new path for realizing thin seam coal mine safety, high efifcient mining.%北宿煤矿通过对采煤机的改造,提高了薄煤层(特别是含有硫化铁结核和硬夹矸薄煤层)综合机械化工艺适用条件,大大降低采煤工人的劳动强度,改善作业环境,为薄煤层矿井实现安全、高效开采探出一条新路子。

  13. The CO2 Geological Sealing Conditions and Potential Evaluation in Coal Seams in Jiangsu Province%江苏省CO2煤层地质封存条件与潜力评价

    Institute of Scientific and Technical Information of China (English)

    姚素平; 汤中一; 谭丽华; 裴文明

    2012-01-01

    The geological conditions of CO2 sequestration in coal seams in Jiangsu Province contain the distribution of Carboniferous-Permian coal measures,coal resources and coal seam reservoir conditions. According to the comprehensive research about the geological conditions of CO2 sequestration in coal seams, the preliminary assessments of the storage potential are made for the coal fields in southern Jiangsu, Xuzhou and Fengpei, respectively. The results show that the coal seams in these coal fields have considerable potential and disposal prospect for CO2 sequestration. The estimate of CO2 storage resources in coal seams in Jiangsu Province is over three hundred million tons of CO2. Among these coal seams .southern Jiangsu coal area could sequester 81 million tons of CO2,Xuzhou coal area of nearly 150 million tons of CO2 and Fengpei coal area of 87 million tons of CO2. The prospect of typical coal-seam CO2 sequestration can be divided into three categories : suitable storage area( Class A), less suitable storage area ( B), and poor storage area ( Class C).%根据江苏省石炭—二叠纪煤系的分布、煤炭资源量和煤层的储集条件等煤封存CO2地质条件的综合研究,分别对苏南煤田、徐州煤田、丰沛煤田煤层封存CO2的潜力进行了初步评估,认为该区CO2煤层封存具有一定的潜力和前景.评估结果表明江苏省煤层可存储CO2总量超过3×108t,其中苏南含煤区可存储CO2容量为8.1×107 t,徐州煤矿区可存储容量近1.5×108t,丰沛煤矿区为8.7× 107t.并对各典型含煤区块CO2煤封存前景进行分类:适合存储区(A类)、较适合存储区(B类)和较差存储区(C类).

  14. Forward modeling to improve seismic reflection energy of a protective coal seam based on Zoeppritz equation

    Institute of Scientific and Technical Information of China (English)

    TAO Wen-peng; DONG Shou-hua; LI Yang

    2008-01-01

    In seismic exploration for coal, seismic waves are very difficult to transmit downward because of high velocity protec-tive layers, making the reflection information very hard to receive above ground. Based on the Snell law and the Zoeppritz equation, we studied the relationship between the incidence angle and reflection seismic wave energy using a forward model of level media. The result shows that the seismic wave energy has a sudden increase at the critical angle. Based on the energy propagation rule, using big offset to receive the seismic wave energy under a protective layer can effectively reduce its protection effect.

  15. Taiyuan Formation Coal Seam No.8 Coal Facies Features in Wangping Minefield, Datong Coalfield%大同煤田王坪井田太原组8号煤层煤相特征

    Institute of Scientific and Technical Information of China (English)

    张文; 刘东娜; 赵峰华

    2015-01-01

    Taking the Taiyuan Formation coal seam No.8 in Wangping minefield, Datong coalfield as subject investigated, using optical microscopic, coal quality analysis, inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence spectrometry (XRF) methods carried out studies on coal petrology, coal quality and coal geochemical characteristics, on these bases analyzed coal fa⁃cies features. The result has shown:1) Macrolithotype of Taiyuan Formation coal seam No.8 in Wangping minefield is semibright coal and semidull coal, macerals have mainly vitrinite and inertinite, microlithotypes have durite and clarite. 2) Coal seam No.8 is low mois⁃ture, medium low ash, medium low sulfur and medium high volatile matter gas coal. 3) Coal seam top and bottom parts belong to terres⁃trial-transitional facies;other slices marine-transitional facies. 4) Coal-forming environment was delta plain flood basin, coal facies were basically open water bog facies, part wet land herbal bog facies;coal seams experienced water level rising and falling two courses, meanwhile since an interrupt of coal accumulation happened, thus reflected on bog environment and coal-forming plants evolutional pattern.%以大同煤田王坪井田太原组8号煤层为研究对象,采用光学显微镜、煤质分析、电感耦合等离子质谱(ICP-MS)和X射线荧光光谱(XRF)等方法探讨了其煤岩学、煤质和煤地球化学特征,并在此基础上分析了其煤相特征。结果表明:(1)王坪井田太原组8号煤层宏观煤岩类型为半亮煤和半暗煤,显微组分以镜质组和惰质组为主,显微煤岩类型为微暗亮煤和微亮暗煤;(2)8号煤为低水、中低灰、中低硫和中高挥发分气煤;(3)煤层顶部和底部属于陆相-过渡相,其余分层为海相-过渡相;(4)成煤环境为三角洲平原的泛滥盆地,煤相基本为开阔水域沼泽相,部分为湿地草本沼泽相;煤层自下而上经历了水位升

  16. Modified Two-Step Dimethyl Ether (DME) Synthesis Simulation from Indonesian Brown Coal

    OpenAIRE

    Dwiwahju Sasongko; Abdurrahman Fadhlil Halim Luthan; Winny Wulandari

    2016-01-01

    A theoretical study was conducted to investigate the performance of dimethyl ether (DME) synthesis from coal. This paper presents a model for two-step DME synthesis from brown coal represented by the following processes: drying, gasification, water-gas reaction, acid gas removal, and DME synthesis reactions. The results of the simulation suggest that a feedstock ratio of coal : oxygen : steam of 1 : 0.13 : 0.821 produces the highest DME concentration. The water-gas reactor simulation at a tem...

  17. Do stable carbon isotopes of brown coal woods record changes in Lower Miocene palaeoecology?

    NARCIS (Netherlands)

    Poole, I.J.; Dolezych, M.; Kool, J.; Burgh, J. van der; Bergen, P.F. van

    2006-01-01

    Stable carbon isotope ratios of fossil wood from the Miocene brown coal deposits in former East Germany are compared with palaeobotanical and sedimentological data to test the use of stable isotopes in determining palaeoenvironment. Significant differences in the chemical composition of samples from

  18. Assessment of Geogenic Contaminants in Water Co-Produced with Coal Seam Gas Extraction in Queensland, Australia: Implications for Human Health Risk

    Directory of Open Access Journals (Sweden)

    William Stearman

    2014-09-01

    Full Text Available Organic compounds in Australian coal seam gas produced water (CSG water are poorly understood despite their environmental contamination potential. In this study, the presence of some organic substances is identified from government-held CSG water-quality data from the Bowen and Surat Basins, Queensland. These records revealed the presence of polycyclic aromatic hydrocarbons (PAHs in 27% of samples of CSG water from the Walloon Coal Measures at concentrations <1 µg/L, and it is likely these compounds leached from in situ coals. PAHs identified from wells include naphthalene, phenanthrene, chrysene and dibenz[a,h]anthracene. In addition, the likelihood of coal-derived organic compounds leaching to groundwater is assessed by undertaking toxicity leaching experiments using coal rank and water chemistry as variables. These tests suggest higher molecular weight PAHs (including benzo[a]pyrene leach from higher rank coals, whereas lower molecular weight PAHs leach at greater concentrations from lower rank coal. Some of the identified organic compounds have carcinogenic or health risk potential, but they are unlikely to be acutely toxic at the observed concentrations which are almost negligible (largely due to the hydrophobicity of such compounds. Hence, this study will be useful to practitioners assessing CSG water related environmental and health risk.

  19. 缓倾斜严重突出煤层快速揭煤优化研究%Research on Optimization of Fast Exposing Gently-inclined Serious Outburst Coal Seam by a Crosscut

    Institute of Scientific and Technical Information of China (English)

    王建; 张荻; 李正刚

    2015-01-01

    为了提高缓倾斜严重突出煤层的揭煤效率,采用缩短揭煤巷道距离、水力压裂增透结合底板穿层钻孔预抽的方法,优化揭煤步骤. 现场应用表明,该方法可以减少2次区域验证次数,减少施工9~24个钻孔,揭煤时间平均缩短5. 0~15. 4 d,费用减少50%,实现了安全快速石门揭煤.%In order to improve the efficiency of exposing the gently-inclined serious outburst coal seam by a crosscut, the steps of exposing the outburst coal seam by a crosscut were optimized by adopting the measures of shortening the distance of the roadway exposing the outburst coal seam, gas permeability enhancement by hydraulic fracturing and gas pre-drainage by floor crossing holes. The site application showed that this method can reduce two regional verifications, reduce the drilling construction of 9~24 holes, the average time for exposing the outburst coal seam was shortened by 5. 0~15. 4 d and the costs were reduced by 50%, as a result, the fast exposing outburst coal seam by a crosscut was realized.

  20. 斜沟井田山西组8号煤层冲刷带预测方法研究%Shanxi Coal Seam No.8 with Erosion Prediction Method in Xiegou Well Field

    Institute of Scientific and Technical Information of China (English)

    郭俊生

    2012-01-01

    斜沟井田山西组属河流相含煤地层,目前开采的8号煤层受河流相顶板砂岩冲刷的范围和程度较大,采掘过程中揭露冲刷带时极难通过,为此如何查清采掘区域内冲刷带的分布特点,优化采掘部署,成为了矿井高产稳产的关键因素.本文通过摸清8号煤层结构和冲刷带沉积机理,利用地质统计学集成分析煤层数据,从而初步掌握了冲刷带预测的方法.%Shanxi coal seam No.8 in Xiegou well field is fluvial coal-bearing seam: currently mined No. 8 coal seam is eroded more and more. In mining process, when uncovering wash zone, it is difficult to get through. How to find out the distribution of erosion zone in the mining region, optimize mining deployment became a key factor of production in mine. This paper tries to find out the No. 8 coal seam structure and erosion zone deposition mechanism, and uses geological statistics to analyze coal seam data, and thus master erosion zone prediction method.

  1. Co-pyrolysis of polymethyl methacrylate with brown coal and effect on monomer production

    Energy Technology Data Exchange (ETDEWEB)

    A. Orinak; L. Halas; I. Amar; J.T. Andersson; M. Adamova [University of P.J. Safarik, Kosice (Slovakia). Faculty of Sciences, Institute of Chemistry

    2006-01-01

    Pyrolysis capillary gas chromatography has been applied to the study of the co-pyrolysis of polymethyl methacrylate (PMMA) with Slovakian brown coal with the aim of finding pyrolysis conditions yielding a maximum amount of methyl methacrylate (MMA). Effects of pyrolysis temperature and PMMA-coal weight ratios were investigated. Capillary gas chromatography coupled with mass spectrometric detector (cGC-MS) was used for MMA identification. The highest yield of MMA in the pyrolysate was obtained at 750{sup o}C. The optimal PMMA-coal weight ratio for maximum MMA production lies in the interval 0.5 mg PMMA and 0.6-0.8 mg brown coal with an MMA yield of 64%. Coal addition to the sample affects species recombination in gaseous phase, augments MMA production at higher temperatures and eliminates degradation products of PMMA and coal pyrolysis. Different conversion diagrams are characteristic for thermal degradation of single PMMA and in the mixture with coal. Detailed mechanism of synergetic effects arisen during co-pyrolysis are not yet known. It was also found that lower pyrolysis temperatures are more suitable to study degradation mechanism and kinetics while higher temperatures are more applicable for identification purposes. MMA decomposes completely at 900{sup o}C. 24 refs., 5 figs., 2 tabs.

  2. Overview of the influence of syn-sedimentary tectonics and palaeo-fluvial systems on coal seam and sand body characteristics in the Westphalian C strata, Campine Basin, Belgium

    Science.gov (United States)

    Dreesen, Roland; Bossiroy, Dominique; Dusar, Michiel; Flores, R.M.; Verkaeren, Paul; Whateley, M. K. G.; Spears, D.A.

    1995-01-01

    The Westphalian C strata found in the northeastern part of the former Belgian coal district (Campine Basin), which is part of an extensive northwest European paralic coal basin, are considered. The thickness and lateral continuity of the Westphalian C coal seams vary considerably stratigraphically and areally. Sedimentological facies analysis of borehole cores indicates that the deposition of Westphalian C coal-bearing strata was controlled by fluvial depositional systems whose architectures were ruled by local subsidence rates. The local subsidence rates may be related to major faults, which were intermittently reactivated during deposition. Lateral changes in coal seam groups are also reflected by marked variations of their seismic signatures. Westphalian C fluvial depositional systems include moderate to low sinuosity braided and anastomosed river systems. Stable tectonic conditions on upthrown, fault-bounded platforms favoured deposition by braided rivers and the associated development of relatively thick, laterally continuous coal seams in raised mires. In contrast, rapidly subsiding downthrown fault blocks favoured aggradation, probably by anastomosed rivers and the development of relatively thin, highly discontinuous coal seams in topogenous mires.

  3. Coal facies studies in Denmark and Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Henrik I. [Geological Survey of Denmark and Greenland (GEUS), Department of Reservoir Geology, Oester Voldgade 10, DK-1350 Copenhagen K (Denmark)

    2004-04-23

    Coal of Jurassic age occurs onshore Denmark and in the Danish North Sea, whereas coal of Carboniferous and Miocene age only occurs in the Danish North Sea and onshore Denmark, respectively. The Lower-Middle Jurassic coals are the most widespread and best documented. Onshore Denmark the coals are of low rank while the Jurassic coals in the North Sea are thermally mature and hydrocarbon generating in the Soegne Basin. The Jurassic coals have a maximum thickness of similar2 m and were formed in coastal plain mires and in inland fresh water mires. The Miocene brown coals, up to similar2 m thick, were formed in an overall deltaic setting. Lower Carboniferous and Palaeogene coals occur in northern Greenland, Middle Jurassic coals in northeast Greenland, and Cretaceous coals in western Greenland. The Middle Jurassic low rank coals have been investigated in detail. The up to similar3.5-m-thick coal seams accumulated in coastal mires and they may have an extraordinary resinite-enriched composition. Only a single Cretaceous coal seam has been investigated with regard to the depositional environment; the seam records drowning of a peat mire. The Lower Carboniferous and Palaeogene coals have not been investigated.

  4. Fuel retrofitting possibilities in pulverised brown coal power plants towards reduction of CO{sub 2} emissions

    Energy Technology Data Exchange (ETDEWEB)

    Agraniotis, Michalis

    2012-07-01

    The thesis intends to assess the potential of two different brown coal substitution concepts as possible options to reduce CO{sub 2} emissions in existing pulverised brown coal power plants. The substitution of brown coal by Solid Recovered Fuels (SRF) is examined as first concept. The second concept regarded is the integration of a lignite pre-drying system in an existing steam cycle and the substitution of raw brown coal by pre-dried brown coal. SRF co-firing is demonstrated in a 600 MWe pulverised brown coal boiler in Germany, while pre-dried brown coal co-firing is demonstrated in a 75 MWth pulverised lignite boiler in Greece. Specific environmental, technological and economic parameters are used for the evaluation according to a multi-criteria analysis approach. The analysis tools adopted include experimental measurement activities in the industrial and semi industrial scale, 3D numerical simulations (CFD), thermodynamic calculations of power plant steam cycles and financial calculations. (orig.)

  5. Algal growth and community structure in a mixed-culture system using coal seam gas water as the water source.

    Science.gov (United States)

    Buchanan, Jessica J; Slater, Frances R; Bai, Xue; Pratt, Steven

    2013-01-01

    Coal seam gas (CSG) is being touted as a transition fuel as the world moves towards low-carbon economies. However, the development of CSG reserves will generate enormous volumes of saline water. In this work, we investigate the potential of using this saline water to support mass algae production. Water and brine from a CSG water treatment facility (1.6 and 11.6 g total dissolved solids per litre (TDS L(-1)) respectively) were inoculated with algal biomass from freshwater and seawater environments and supplemented with nutrients in open, fed-batch reactors. Significant algal growth was recorded, with maximum specific growth rates in CSG water and CSG brine of 0.20 +/- 0.05 d(-1) and 0.26 +/- 0.04 d(-1) respectively. These maximum specific growth rates were equal to or greater than specific growth rates in deionized water and seawater diluted to the same salinity. However, algal growth lag time in CSG brine was between 7 and 9 times longer than in other waters. Microscopy and terminal-restriction fragment length polymorphism (T-RFLP) were used to monitor community structure in the reactors. The same few algal species dominated all of the reactors, except for the CSG brine reactor at day 15. This result indicates that conditions in CSG brine select for different species of algae compared to seawater of the same salinity and other waters tested. The findings suggest that mass algae production in CSG water is feasible but algae community composition may be a function of CSG water chemistry. This has implications for the downstream use of algae.

  6. PYROLYSIS OF BROWN COAL USING A CATALYST BASED ON W–Ni

    Directory of Open Access Journals (Sweden)

    Lenka Jílková

    2015-10-01

    Full Text Available Tars from pyrolysis of brown coal can be refined to obtain compounds suitable for fuel production. However, it is problematic to refine the liquids from brown coal pyrolysis, because high molecular compounds are produced, and the sample solidifies. Therefore we decided to investigate the possibility of treating the product in the gas phase during pyrolysis, using a catalyst. A two-step process was investigated: thermal-catalytic refining. In the first step, alumina was used as the filling material, and in the second step a catalyst based on W-Ni was used. These materials were placed in two separate layers above the coal, so the volatile products passed through the alumina and catalyst layers. Pyrolysis tests showed that using the catalyst has no significant effect on the mass balance, but it improves the properties of the gas and the properties of the organic part of the liquid pyrolysis products, which will then be processed further.

  7. Determination of Gas Extraction Radius in Coal Seams by Tracer Technique with SF6%利用SF6示踪技术测试煤层瓦斯抽采半径

    Institute of Scientific and Technical Information of China (English)

    辛明

    2012-01-01

    为了合理布置煤层抽放钻孔数量,采用SF6示踪技术测定煤层瓦斯抽采半径.沿煤层布置一排试验钻孔,选定其中某几个孔作为SF6释放孔,其余作为抽采试验孔,在一定的抽采负压条件下,通过观测抽采试验孔的瓦斯浓度随时间的变化情况,可以确定煤层瓦斯抽采半径.在朱集矿的试验中,通过一个月的连续观测,测得该矿11-2煤层瓦斯抽采半径可以达到5m.利用SF6示踪气体可以较好的测定煤层瓦斯抽采半径.%In order to rationably determine the numer of boreholes for gas extraction in coal seams, gas extraction radius in coal seams was tested by using tracer technique with SF6. One row of testing boreholes in coal seam were performed, some of which are selected as SF6 releasing boreholes, the rest as gas extraction boreholes. Under certaine extraction depress in testing boreholes by observing gas concentration changes with time, gas extraction radius in coal seams was determined. In test in Zhuji Coal Mine, for one month of continuous observation, gas extraction radius in coal seam 11-2 was measured as 5 m. By using tracer technique with SF6, gas extraction radius in coal seams can be accurately determined.

  8. Variability of production in the Tito brown coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, S. (Institut za Rudarska Istrazivanja, Tuzla (Yugoslavia))

    1987-05-01

    Examines daily production fluctuations in the Banovici coal basin from 1978-1985, where 2,800-4,100 workers produced 2-2.3x10{sup 6} t/a from underground and surface mines. The underground mine used mechanized longwall mining, surface mines employed shovel excavators, draglines, dumpers and belt conveyors. Statistical data showed large variations (+/- 2.5%, from 4,630 to 7,792 t/day) in daily coal production; evaluation showed close correlations for surface and underground mines. Highest production was achieved on Saturdays and Sundays, lowest on Mondays, Wednesdays and Fridays. It is suggested that these variations may be due to maintenance work in the coal preparation plant, which was usually carried out on Mondays and Fridays. A stereogram of coal and overburden output for both types of mine and detailed statistical computations are included. 7 refs.

  9. Parameters determining the carbon isotopic composition of coal and fossil wood in the Early Miocene Oberdorf lignite seam (Styrian Basin, Austria)

    Energy Technology Data Exchange (ETDEWEB)

    Bechtel, A.; Sachsenhofer, R.F.; Gratzer, R.; Lucke, A.; Puttmann, W. [University of Leoben, Leoben (Austria)

    2002-07-01

    Petrographical and geochemical data of gelified and ungelified fossil wood from the Early Miocene Oberdorf lignite seam (Styrian Basin, Austria) provide evidence that the early diagenetic, aerobic degradation of wood by fungi may be followed by further decomposition under reducing conditions by the activity of anaerobic bacteria. Based on the molecular compositions of terpenoid hydrocarbons, the wood fragments in the lignite are identified as gymnosperms. The mean carbon isotope values found for gymnosperms and coals (-24.2 parts per thousand and -24.7 parts per thousand, respectively) confirm the results from biomarker analyses indicating that the peat-forming vegetation of the Oberdorf seam was dominated by gymnosperm taxa. The results obtained from the Early Miocene Oberdorf lignite indicate that the carbon isotope ratios of the coals are primarily affected by varying contributions of different parts of whole-plant tissue, due to their different isotopic and molecular compositions (e.g. epicuticular leaf waxes, resins, wood) and their different decay-resistance against the early diagenetic changes involved in organic matter decomposition. Carbon cycling during anoxic decomposition of plant-derived organic matter is assumed to affect the {delta}-{sup 13}C values of coal. {delta}-{sup 13}C Values of wood and extracted cellulose are affected only to a minor extent.

  10. Approach to increasing the quality of pressure-relieved gas drained from protected coal seam using surface borehole and its industrial application

    Institute of Scientific and Technical Information of China (English)

    Yingke Liu; Fubao Zhou; Jianlong Wang; Jun Liu

    2015-01-01

    During mining of lower protective coal seam, a surface borehole can efficiently extract not only the pressure-relieved gas from the protected layer, but also the gas from the mining layer gob. If the distance between the borehole and gob is too large, the quantity of gas drained from the protected layer decreases substantially. To solve this problem, a mathematical model for extracting pressure-relieved gas from a protected coal seam using a surface borehole was established, based on the radial gas flow theory and law of conservation of energy. The key factors influencing the quantity of gas and the drainage flow network using a surface borehole were presented. The results show that the quantity of pressure-relieved gas drained from the protected layer can be significantly increased by increasing the flow resistance of the borehole bottom. Application of this method in the Wulan Coal Mine of the Shenhua Group significantly increased the flow of pure gas and the gas concentration (by factors of 1.8 and 2.0, respectively), thus demonstrating the remarkable effects of this method.

  11. 图像识别技术在煤层识别中的应用%Application of Image Recognition Technology in Coal Seam Identification

    Institute of Scientific and Technical Information of China (English)

    林雯

    2013-01-01

    T he image recognition technology is widely used in geological exploration, seam exploration,meteorological exploration and other fields. In the paper, the coal and rock boundaries identification technology currently used widely is analyzed. the coal seam recognition techhology is proposed. At last, these technologies are integrated into the album acquisition system. These have some positive significance for the future coal mining unattended and fully automated mining.%图像识别技术在地质勘探、煤层勘探、气象勘探等领域被广泛应用。文章分析了当前应用比较广泛的煤岩界识别技术,提出了基于图像识别技术的煤层识别方法,最后将这些技术融合到专辑采集系统中。这些对未来煤矿实现无人值守开采,全自动化开采具有一定的积极意议。

  12. Petrographic and geochemical characterization of pale and dark brown coal from Yunnan Province, China

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Q.; Xilin, R.; Dazhong, T.; Jian, X.; Wolf, M. [Aachen University, Aachen (Germany). Lehrstuhl fuer Geologie, Geochemie und Lagerstaetten des Erdoels und der Kohle

    1994-01-01

    Fifteen lignite samples from the province of Yunnan were analysed by organic petrography and geochemistry. Twelve of the samples represent the very pale (yellow) Baipao coal, the other three were normal coals of a medium brown colour. The Baipao coal consists mainly of mineral-bituminous groundmass, whereas the normal coal is characterised by well-preserved tissues derived from gymnosperm wood. Up to 190 mg/g C{sub org} of extract is extractable from the Baipao coal; only 63 mg/g C{sub org} from the normal coal. The n-alkaline fraction of the Baipao coal extract consists of high amounts of hopanes and shows the predominance of nor-abietane within the diterpenoids present. The first group of compounds points to intensive bacterial activity, while the second compound indicates not only that gymnosperms are present but also that a relatively oxygen-rich environment existed at the time of deposition. From the petrographic and organic geochemical characteristics it is concluded that the Baipao coal was formed from the same plant source material as the normal coal, but underwent stronger decay. 22 refs., 11 figs., 2 plates, 8 tabs.

  13. Nickel-catalyzed hydroliquefaction of Morwell brown coal at low temperatures using phenolic compounds as solvents

    Energy Technology Data Exchange (ETDEWEB)

    Takemura, Y.; Saito, Y.; Okada, K.; Koinuma, Y.

    To attain a more effective coal liquefaction process, low-temperature (230-270 degrees C) coal hydroliquefaction was performed by using 15 kinds of single- or double-ring phenolic compounds as solvents and nickel acetate as a catalyst precursor. The role of the phenolic compound in the liquefaction reaction is discussed. With selected compounds, such as 1,7-dihydroxynaphthalene and resorcinol, Morwell brown coal was catalytically liquefied in a batch autoclave under H/sub 2/ pressure (10 MPa, cold) to give the coversions of the coal (to benzene/ethanol mixture solubles), which are higher than 70 wt%, at 270 degrees C for 1 h. Among three dihydroxybenzenes, resorcinol showed the highest efficiency for the Ni-catalyzed hydroliquefaction of the coal, though the capability of resorcinol to dissolve coal is the lowest in the absence of H/sub 2/. Capabilities of o-phenylphenol and its related compounds to dissolve the coal at 250 degrees C under Ar pressure (10 MPa, cold) and to hydroliquefy the coal at 270 degrees C under H/sub 2/ pressure (10 MPa, cold) were quantified. The respective orders of the conversion of the coal with these compounds are as follows: o-phenylphenol approximately equal to o-cyclohexylphenol > biphenyl approximately equal to cyclohexylbenzene. At this temperature, the solvent effect of phenolic functionality is larger than that of the hydroaromatic one. The same result is found with 1-naphthol and 5,6,7,8-tetrahydro-1-naphthol. 20 refs., 4 tabs.

  14. Performance Analysis of Fractured Wells with Stimulated Reservoir Volume in Coal Seam Reservoirs

    Directory of Open Access Journals (Sweden)

    Yu-long Zhao

    2016-01-01

    Full Text Available CoalBed Methane (CBM, as one kind of unconventional gas, is an important energy resource, attracting industry interest in research and development. Using the Langmuir adsorption isotherm, Fick’s law in the matrix and Darcy flow in cleat fractures, and treating the Stimulated Reservoir Volume (SRV induced by hydraulic fracturing as a radial composite model, the continuous linear source function with constant production is derived by the methods of the Laplace transform and Duhamel theory. Based on the linear source function, semi-analytical solutions are obtained for a fractured vertical well producing at a constant production rate or constant bottom-hole pressure. With the help of the Stehfest numerical algorithm and computer programing, the well test and rate decline type curves are obtained, and the key flow regimes of fractured CBM wells are: wellbore storage, linear flow in SRV region, diffusion flow and later pseudo-radial flow. Finally, we analyze the effect of various parameters, such as the Langmuir volume, radius and permeability in the SRV region, on the production performance. The research results concluded in this paper have significant importance in terms of the development, well test interpretations and production performance analysis of unconventional gas.

  15. Upgrading of brown coal by slurry-dewatering; Kattan no yuchu dassui ni yoru clean kotai nenryo no seizo

    Energy Technology Data Exchange (ETDEWEB)

    Okuma, O.; Shimizu, T.; Inoue, T.; Shigehisa, T.; Deguchi, T.; Katsushima, S. [Kobe Steel, Ltd., Kobe (Japan)

    1996-10-28

    This paper describes an outline of solid fuel production process from brown coal and the investigation results of its elemental techniques. Dried coal is produced by this process which consists of a dewatering of crushed brown coal in oil-based solvent, a solid and liquid separation of slurry, and a remained oil recovery by heating. This process is characterized by the higher thermal efficiency compared with usual drying and the restraint of spontaneous combustion of product coal. It was revealed that solid fuel with low moisture, low ash, low sulfur, and suppressed spontaneous combustion property can be produced from Australian brown coal through this process. From the comparison between kerosene and fuel oil A, it was confirmed that the oil content during dewatering was smaller and the oil recovery by heating was easier by using a solvent with lower boiling point. It was also confirmed that the spontaneous combustion property can be suppressed using small amount of asphalt by solving asphalt in the solvent and adsorbing asphalt on the surface of brown coal. From these results, low rank coals including brown coal, which are difficult to use, are expected to be used as clean coal with low ash and low sulfur through this process. 2 refs., 7 figs., 2 tabs.

  16. Hydrochemical evolution within a large alluvial groundwater resource overlying a shallow coal seam gas reservoir.

    Science.gov (United States)

    Owen, Daniel D R; Cox, Malcolm E

    2015-08-01

    A combination of multivariate statistical techniques, simple hydrochemical mixing models and inverse geochemical modelling was used to investigate the major hydrochemical evolutionary pathways of a large alluvial aquifer, the upper Condamine River alluvium, south-east Queensland, Australia. Hydrochemical similarities between alluvium and sedimentary bedrock groundwater imply some mixing between alluvial and sedimentary bedrock aquifers, but spatial assessment showed that this was localised around outcrops of sedimentary bedrock in upstream areas. Within the alluvium, a distinct shift towards a low salinity Na-HCO3 water type and a brackish Na-HCO3-Cl water type was obvious in two separate locations. Both of these water types are unique to the alluvium, and inverse modelling shows that they can evolve via a combination of in situ alluvial processes, including diffuse recharge of rainfall or river water or the evolution of basalt-derived groundwater via gypsum dissolution plagioclase weathering, cation exchange and some carbonate precipitation/dissolution. The evolution of these water types is potentially influenced by overlying sodic alkaline soils, and often is associated with a source of sulfate. Evapotranspiration is the dominant salinization process in the alluvium and increases in calcium cations during salinization indicate that brackish Na-HCO3-Cl groundwater in the underlying Walloon Coal Measures are unlikely to have a major influence on salinization in the alluvium. The most saline water types observed were endemic to shallow zones of the alluvium where evapotranspiration is likely. Results demonstrate that a combination of multivariate statistics and inverse geochemical modelling can be successfully used to delineate hydrochemical pathways in complex hydrogeological settings where a range of environmental and anthropogenic factors may be influencing the evolution of water types with similar hydrochemical compositions.

  17. Numerical Simulation of Coal and Gas Outburst Process in Uncovering Frozen Coal Seam in Cross - Cut%石门揭露冻结煤层瓦斯突出过程的数值模拟

    Institute of Scientific and Technical Information of China (English)

    谢雄刚; 冯涛; 余照阳

    2012-01-01

    针对新提出的石门揭煤注液冻结防突方法,根据煤与瓦斯突出与煤层力学性能、煤层冻结温度之间的关系,结合人工冻结工程实践,采用岩石破裂过程分析RFPA2D系统,确定模型尺寸和边界条件,建立了石门揭露冻结煤层过程气固耦合数学模型。设定冻结温度下煤层的单轴抗压强度、弹性模量及瓦斯压力等相关参数,数值模拟了不同冻结温度下龙家山煤矿-400m水平2#石门揭露6#煤层过程。数值模拟表明:当6#煤层温度降为-10--20℃时,该石门揭煤工作面突出危险性将大为降低。综合冻结时间、能源消耗和防突效果,选定-10℃作为该石门揭露冻结煤层控制温度,可以提高突出矿井石门揭煤工程的经济效益。%Aiming at a new- presented outburst prevention method by injecting liquid and freezing in uncovering coal seam in cross - cut, according to the relationship among the coal and gas outburst, the mechanical properties and coal seam freezing temperature, and combining with artificial freezing engineering practice, with the reek failure process analysis software - RFDA2D, the paper determines the model sizes and boundary conditions and establishes gas and solid coupling mathematics model of uncovering frozen coal seam in cross - cut. Setting the interrelated parameters of gas pressure, uniaxial compressive strength and elastic modulus of coal seam under freezing temperature, the paper simulates the process of uncovering 6# freezing coal seam in 2# cross - cut of - 400 levels in Longjias- hart mine under the different freezing temperature. The simulation shows that when the temperature of 6# frozen coal seam drops to - 15 - -20℃, the gas outburst risk of the working face in 2# rock cross -cut will be greatly reduced. Integrating freezing time, energy consumption and outburst prevention effect, -10℃ is selected as the frozen seam control temperature of the working face, which can

  18. Coal matrix swelling during CO2 sequestration in deep coal seams:A perspective%深部煤层封存 CO2过程中的煤基质溶胀效应

    Institute of Scientific and Technical Information of China (English)

    王浩浩; 张登峰; 王倩倩; 彭健; 霍培丽

    2015-01-01

    强化煤层气甲烷(CH4)采收率的深部煤层封存二氧化碳(CO2)技术能够将主要人为温室气体(CO2)进行有效的地质存储。考虑到 CO2流体和煤体的自身特性,封存过程中的 CO2流体将会诱导煤基质发生溶胀效应。溶胀效应将会对煤层封存 CO2技术构成潜在的影响。为此,本文结合国内外相关研究工作,归纳了流体诱导煤基质溶胀的规律,指出了煤基质溶胀对煤层封存 CO2过程的影响,介绍了流体诱导煤基质溶胀的分析手段,提出了封存过程中煤基质溶胀的研究趋势。分析表明:①煤基质溶胀程度与流体种类、压力、温度和煤的变质程度有关;②CO2诱导煤基质溶胀效应将会降低煤层的渗透性能,进而影响 CO2等流体在煤层内部的有效运移;③溶胀效应会影响煤层的 CO2封存性能,建立涉及溶胀效应的煤吸附理论模型是溶胀效应研究的重要课题;④煤基质溶胀机理及其可逆性能研究目前存在争议,研究人员需要从煤体理化结构的研究出发以明确上述问题。%Carbon dioxide (CO2) sequestration in deep coal seams with enhanced coal-bed methane (CH4) recovery (CO2-ECBM) can store the main anthropogenic greenhouse gas (CO2) in geological time. In consideration of the properties of both CO2 and coal,swelling effect induced by CO2 will occur during the sequestration process. The swelling effect can show negative effect on CO2 sequestration in coal seams. Therefore, the recent research progress in coal swelling during sequestration process has been summarized. The effects of fluid on coal swelling were concluded,and the influences of coal swelling on sequestration process were analyzed. The analytical methods for coal swelling were provided and the future trends of coal matrix swelling during CO2 sequestration in deep coal seams were also pointed out. The results indicate that coal swelling is related to fluid type

  19. Simulating isolation of liquid products from brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Somov, A.M.; Ustyuzhanina, G.P.; Proskuryakov, V.A.

    1988-10-20

    A model was constructed describing the volatile release from coal based on the pyrolysis mechanism and identification of the major elements in relation to the conditions. Pyrolysis involves the following stages: heating, primary decomposition, decomposition-product diffusion in the particles, and external mass transfer. The model gives a complete kinetic description for the release of liquid products. The description is dependent on the rate relations and incorporates the nonstationary temperature distribution along with the effect of coal particle diameter on liquid product yield. The model has been used to define parameters and identify two critical particle diameters enabling one to define the semicoking range.

  20. Nanoporosity development in the thermal-shock KOH activation of brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Kucherenko, V.A.; Shendrik, T.G.; Tamarkina, Y.V.; Mysyk, R.D. [LM Litvinenko Institute of Physical Organic & Coal Chemistry, Donetsk (Ukraine)

    2010-12-15

    Thermal-shock KOH activation of brown coal (800 degrees C, KOH/coal ratio 1 g/g) was shown to produce nanoporous activated carbon with more developed surface area than thermally-programmed heating (S-BET up to 1700 vs 1000 m{sup 2}/g). Increasing the KOH/coal ratio (up to 1 g/g) in the activated mixture increases the total pore volume (0.14-1.0 cm{sup 3}/g), the micropore volume (0.03-0.71 cm{sup 3}/g), and also the volume of subnanometer pores (0.01-0.40 cm{sup 3}/g). Thermal shock produces nanoporosity at lower KOH/coal ratios (0.5-1.0 g/g) than respective low-rate heating KOH activation.

  1. Effects of fractal surface on rheological behavior and combustion kinetics of modified brown coal water slurries

    Institute of Scientific and Technical Information of China (English)

    Zhifang Gao; Shuquan Zhu; Mingdong Zheng; Zhaojin Wu; Huihong Lu; Weiming Liu

    2015-01-01

    The paper reports the effects of surface fractal structures on the rheological behavior and combustion kinetics of raw brown coal and three modified coal water slurries (CWSs). The results show that the fractal structures and physicochemical properties of samples are dependent on various modification processes. The apparent viscosities of the coal water slurries increase with increasing surface fractal dimensions (D), especially with decreasing shear rates. Fur-thermore, it has been proved that the ignition temperatures and apparent activation energies of modified CWSs are lower than that of raw coal water slurry. Compared with the traditional qualitative analysis of the effect of pore structures on CWSs properties, D can more efficiently indicate the quantificational effect of pore structures on the rheological behavior and combustion kinetics of CWSs.

  2. 厚煤层瓦斯抽放钻车研制%Development of Drilling Car for Thick Coal Seam Gas Drainage

    Institute of Scientific and Technical Information of China (English)

    李旭珍; 李强

    2016-01-01

    Based on the requirements of coal mine tunnel gas drainage drilling ,the tunnel gas drainage drilling cars were studied ,and a deep‐hole drilling car for thick coal seam was developed ,which could effectively reduce the auxiliary work time and improve the working efficiency .%根据厚煤层矿井坑道瓦斯抽放钻孔的要求,对坑道瓦斯抽放钻机进行了研究,研制了适合厚煤层钻孔施工的煤矿用深孔钻车,有效地减少了辅助工作时间,提高了工作效率。

  3. Mapping the hydraulic connection between a coalbed and adjacent aquifer: example of the coal-seam gas resource area, north Galilee Basin, Australia

    Science.gov (United States)

    Jiang, Zhenjiao; Mariethoz, Gregoire; Schrank, Christoph; Cox, Malcolm; Timms, Wendy

    2016-12-01

    Coal-seam gas production requires groundwater extraction from coal-bearing formations to reduce the hydraulic pressure and improve gas recovery. In layered sedimentary basins, the coalbeds are often separated from freshwater aquifers by low-permeability aquitards. However, hydraulic connection between the coalbed and aquifers is possible due to the heterogeneity in the aquitard such as the existence of conductive faults or sandy channel deposits. For coal-seam gas extraction operations, it is desirable to identify areas in a basin where the probability of hydraulic connection between the coalbed and aquifers is low in order to avoid unnecessary loss of groundwater from aquifers and gas production problems. A connection indicator, the groundwater age indictor (GAI), is proposed, to quantify the degree of hydraulic connection. The spatial distribution of GAI can indicate the optimum positions for gas/water extraction in the coalbed. Depressurizing the coalbed at locations with a low GAI would result in little or no interaction with the aquifer when compared to the other positions. The concept of GAI is validated on synthetic cases and is then applied to the north Galilee Basin, Australia, to assess the degree of hydraulic connection between the Aramac Coal Measure and the water-bearing formations in the Great Artesian Basin, which are separated by an aquitard, the Betts Creek Beds. It is found that the GAI is higher in the western part of the basin, indicating a higher risk to depressurization of the coalbed in this region due to the strong hydraulic connection between the coalbed and the overlying aquifer.

  4. Research on Propagation Characteristics of Audio Electromagnetic Waves in Coal Seams%煤层中音频电磁波传播特性的研究

    Institute of Scientific and Technical Information of China (English)

    连杰; 冯宏; 王继矿

    2012-01-01

    超前探测监测煤层中的地质异常体,是保障矿井安全生产的重要工作之一.文章从信号传播常数的衰减方面,研究了音频电磁波在三层层状煤层中的传播特性,并提出尝试运用音频电透视技术监测工作面地质情况,为音频电透视仪器的进一步发展奠定基础.%The advanced detection and monitoring on geological anomalous bodies in coal seam is one of the important works of guaranteeing safe production mine. This article studies the propagation characteristics of audio electromagnetic waves in three-layered coal seams from the attenuation of signal propagation constant, and proposes to try to use audio electricity perspective technology to monitor geological conditions of working face, so as to lav the foundation of further development of audio electricity perspective instrument.

  5. 滴道盛和煤矿立井18~#煤层瓦斯地质规律分析%Laws Analysis of Gas Geology in Vertical Shaft of Didaoshenghe Coal Mine No.18 Coal Seam

    Institute of Scientific and Technical Information of China (English)

    苏广福

    2012-01-01

    在现场收集大量瓦斯与地质资料的基础上,结合大量的实测数据,采用瓦斯与地质理论相结合的方法,定性定量分析了滴道盛和煤矿立井18#煤层的瓦斯地质规律。分析了地质构造、煤层顶底板岩性、岩浆岩侵入、煤层底板标高对瓦斯赋存的影响,并对矿井瓦斯涌出量进行了预测。%On the basis of on-site collecting a lot of gas and geological data,with a large number of measured data,Using a method of combining gas and geological theory,gas geology laws in vertical shaft of Didaoshenhe coal mine No.18 coal seam are analyzed qualitatively and quantitatively.The influencing of geological structure,roof and floor lithologic,magmatic intrusion and coal seam floor elevation on gas occurrence is analyzed,and the gas emmission of coal mine is predicted.

  6. The competitive strength of German brown coal; Deutsche Braunkohle im Wettbewerb

    Energy Technology Data Exchange (ETDEWEB)

    Henning, D.

    1997-01-01

    On the occasion of a celebration on 4 December 1996, Dr.-Ing. Dieter Henning, Chairman of the Board of Rheinbraun-AG, outlined the changes in the energy-political boundary conditions in Germany and Europe, strategies for maintaining the competitive strength of brown coal, and the importance of this feld of industry, and especially of the Garzweiler II oopen-cast mine, for the structural development of the Rhenish brown coal district. (orig.) [Deutsch] Die gemeinsame Barbara-Feier am 4. Dezember 1996 in der Erfthalle Kerpen-Tuernich war dem Vorstandsvorsitzenden der Rheinbraun AG, Bergwerksdirektor Dr.-Ing. Dieter Henning Anlass genug, von den Fuehrungskraeften des Rheinischen Braunkohlenbergbaus und den Bergingenieuren vom Bezirksverein Rheinische Braunkohle, die Veraenderungen der energiewirtschaftlichen Rahmenbedingungen in Deutschland und Europa, die Sicherung der Wettbewerbsfaehigkeit der Braunkohle und die Bedeutung dieses Industriezweiges und vor allem von Garzweiler II fuer die strukturelle Entwicklung des rheinischen Reviers, darzulegen. (orig.)

  7. Mechanochemical activation of iron ore-based catalysts for the hydrogenation of brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, P.N.; Kuznetsova, L.I.; Chumakov, V.G.; Moiseeva, G.A. [Rossijskaya Akademiya Nauk, Krasnoyarsk (Russian Federation). Inst. of Chemistry and Chemical Technology

    2000-10-01

    Genesis of pyrrhotite catalysts from different iron ore concentrates and pure iron oxides was investigated using the method of mechanochemical treatment in a planetary mill. The dispersion and fine crystalline structure of oxide and pyrrhotite particles were studied as the function of mechanical load, sulfiding temperature and mode of preparation. Methods for the preparation of high performance iron ore-based catalysts for brown coal hydrogenation have been developed. (orig.)

  8. Reduction of climate-relevant gaseous emissions by CO{sub 2} storage in coal seams: The RECOPOL project; Reduzierung von Treibhausgas-Emissionen durch CO{sub 2}-Speicherung in Kohlefloezen: das RECOPOL Projekt

    Energy Technology Data Exchange (ETDEWEB)

    Krooss, B.M.; Busch, A. [Rheinisch-Westfaelische Technische Hochschule Aachen (RWTH) (Germany); Kretzschmar, H.-J.; Froebel, J. [DBI Gas- und Umwelttechnik GmbH, Leipzig (Germany); Bergen, F. van; Pagnier, H. [NITG-TNO, Utrecht (Netherlands)

    2004-07-01

    In the coal district of Katowice, Poland, the first European field test of long-term storage of CO2 in non-workable coal seams is currently being carried out. The project by the name of RECOPOL (Reduction of CO2 emission by means of CO2 storage in coal seams in the Silesian Coal Basin of Poland) is funded by the EU and will serve to provide a comprehensive analysis of the technical and economic feasibility of this storage concept in the geological and infrastructural conditions prevailing in Central Europe. Further, it was investigated whether injection of CO2 into coal seams will lead to enhanced coal bed recovery. The contribution describes the scientific and technical preparations and accompanying research, the construction of the pilot well, and the state of preparations for CO2 injection. (orig.) [German] Im oberschlesischen Kohlerevier, unweit von Kattowitz (Katowice), findet zurzeit der erste europaeische Feldversuch zur langfristigen Speicherung des Treibhausgases Kohlenstoffdixoid (CO{sub 2}) in nicht-abbaubaren Steinkohlefloezen statt. Ziel des von der Europaeischen Gemeinschaft gefoerderten Forschungsprojektes unter dem Namen RECOPOL (Reduction of CO{sub 2} emission by means of CO{sub 2} storage in coal seams in the Silesian Coal Basin of Poland) ist die umfassende Analyse der technischen und oekonomischen Realisierbarkeit dieses Speicherkonzeptes unter den in Mitteleuropa vorherrschenden geologischen und infrastrukturellen Bedingungen. Weiter soll untersucht werden, ob die Injektion von CO{sub 2} in die Kohlefloeze zu einer Steigerung der Floezgasproduktion fuehrt (Enhanced Coal Bed Methane recovery). Der Beitrag beschreibt die wissenschaftlich-technischen Vorarbeiten und Begleitforschung des Projektes, die Erstellung der Pilotbohrung und den aktuellen Stand der Vorbereitungen fuer die CO{sub 2} Injektion. (orig.)

  9. The immersion freezing behavior of ash particles from wood and brown coal burning

    Science.gov (United States)

    Grawe, Sarah; Augustin-Bauditz, Stefanie; Hartmann, Susan; Hellner, Lisa; Pettersson, Jan B. C.; Prager, Andrea; Stratmann, Frank; Wex, Heike

    2016-11-01

    It is generally known that ash particles from coal combustion can trigger ice nucleation when they interact with water vapor and/or supercooled droplets. However, data on the ice nucleation of ash particles from different sources, including both anthropogenic and natural combustion processes, are still scarce. As fossil energy sources still fuel the largest proportion of electric power production worldwide, and biomass burning contributes significantly to the global aerosol loading, further data are needed to better assess the ice nucleating efficiency of ash particles. In the framework of this study, we found that ash particles from brown coal (i.e., lignite) burning are up to 2 orders of magnitude more ice active in the immersion mode below -32 °C than those from wood burning. Fly ash from a coal-fired power plant was shown to be the most efficient at nucleating ice. Furthermore, the influence of various particle generation methods on the freezing behavior was studied. For instance, particles were generated either by dispersion of dry sample material, or by atomization of ash-water suspensions, and then led into the Leipzig Aerosol Cloud Interaction Simulator (LACIS) where the immersion freezing behavior was examined. Whereas the immersion freezing behavior of ashes from wood burning was not affected by the particle generation method, it depended on the type of particle generation for ash from brown coal. It was also found that the common practice of treating prepared suspensions in an ultrasonic bath to avoid aggregation of particles led to an enhanced ice nucleation activity. The findings of this study suggest (a) that ash from brown coal burning may influence immersion freezing in clouds close to the source and (b) that the freezing behavior of ash particles may be altered by a change in sample preparation and/or particle generation.

  10. 模糊集合在煤变质程度与煤层气预测中的应用%The Application of Fuzzy Sets in Forecasting Coal Metamorphic Degree and Coal Seam Gas

    Institute of Scientific and Technical Information of China (English)

    李东; 张学梅; 程实; 王震

    2015-01-01

    煤的变质(煤化)程度在很大程度上决定了煤层最终的生烃能力和煤层气吸附能力的强弱. 煤的变质(煤化)程度可以用最大反射率Rmax来判定. 用计算所得强度指数(SI)和组分平衡指数(CBI)作为自变量,最大反射率(R)max为因变量,得到的回归方程就是煤的变质程度与最大反射率(R)max的非线性函数关系. 因此,最大反射率(R)max与煤的生气量或煤的吸附煤层气能力是非线性的函数关系.%The metamorphic degree of coal is a predominated factor which determines both the methane production capacity from seams and the methane adsorption capacity of seams. The metamorphic degree of coal can be evaluated through the maximum reflectivity (R)max. Using the strength index (SI) and composition balance index (CBI) as the independent variables, and the maximum reflectivity (R)max as dependent variable, a regression equation is obtained, which shows a nonlinear relationship. Therefore, the maximum reflectivity (R)max should have non-linear relationship with the methane production capacity from seams and the methane adsorption capacity of seams.

  11. Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins

    Science.gov (United States)

    Owen, D. Des. R.; Shouakar-Stash, O.; Morgenstern, U.; Aravena, R.

    2016-08-01

    Using a comprehensive data set (dissolved CH4, δ13C-CH4, δ2H-CH4, δ13C-DIC, δ37Cl, δ2H-H2O, δ18O-H2O, Na, K, Ca, Mg, HCO3, Cl, Br, SO4, NO3 and DO), in combination with a novel application of isometric log ratios, this study describes hydrochemical and thermodynamic controls on dissolved CH4 from a coal seam gas reservoir and an alluvial aquifer in the Condamine catchment, eastern Surat/north-western Clarence-Moreton basins, Australia. δ13C-CH4 data in the gas reservoir (-58‰ to -49‰) and shallow coal measures underlying the alluvium (-80‰ to -65‰) are distinct. CO2 reduction is the dominant methanogenic pathway in all aquifers, and it is controlled by SO4 concentrations and competition for reactants such as H2. At isolated, brackish sites in the shallow coal measures and alluvium, highly depleted δ2H-CH4 (gas reservoir (200-500 m) to the shallow coal measures (<200 m) or the alluvium was not observed. The study demonstrates the importance of understanding CH4 at different depth profiles within and between aquifers. Further research, including culturing studies of microbial consortia, will improve our understanding of the occurrence of CH4 within and between aquifers in these basins.

  12. Research into methods of dust prevention in mechanised winning in thin coal seams. Investigacion de metodos de prevencion del polvo, en el arranque mecanizado de capas estrechas de carbon

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Fidalgo, M.; Alvarez Santullano, L.; Eguidazu Pujades, J.L.; Gonzalez del Valle, S.; Cordera Fernandez, J.V.; De Arriba de la Iglesia, J. (Instituto Nacional de Silicosis (Spain))

    1989-09-01

    Concerns the research work carried out jointly by HUNOSA and the National Institute of Silicosis regarding dust prevention on mechanised faces in thin coal seams using shearers with a drum diameter of less than 600 mm. This work was supported by the Directorate General for mines and Ocicarbon. 10 figs., 1 tab.

  13. Numerical simulation of stress distributions and displacements around an entry roadway with igneous intrusion and potential sources of seam gas emission of the Barapukuria coal mine, NW Bangladesh

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Md. Rafiqul; Shinjo, Ryuichi [Department of Physics and Earth Sciences, University of the Ryukyus, Okinawa, 903-0213 (Japan)

    2009-06-01

    This paper uses two-dimensional boundary element method (BEM) numerical modeling to analyze the deformation and failure behavior of a coal seam and to understand the nature of gas flow into a roadway entering the Barapukuria coal mine in Bangladesh. The Barapukuria basin contains Permian-aged Gondwana coals with high volatile B bituminous rank. Three models (A, B, and C) are presented here. Model A assumes horseshoe-shaped geometry, model B assumes trapezoid-shaped geometry, and model C assumes horseshoe-shaped geometry coupled with a roof fall-induced cave generated by the break-up of rock materials along the vertical dimension of an igneous dyke. The simulation results show that there is little difference in strata deformation between models A and B. In model A, there is no horizontal tensional stress and the overall horizontal stress patterns are compressive, while the distribution and magnitude of vertical stress show higher tensional stresses on the immediate rib sides and floor. In model B, both horizontal and vertical stress distributions indicate low to medium tensional stresses on the immediate roof, floor, and rib sides, but compressive stresses are prominent toward the interior of the coal seam. Deformation vectors indicate that failure extends laterally to about 7.5 m around the excavation geometry. On the contrary, for model C, the distributions and magnitudes of horizontal and vertical stress show higher tensional stresses in both rib sides of the roof fall zone. The deformation around the dyke-induced perturbation zone affects a large volume of coal. The deformation vectors with high magnitudes are nearly horizontal and propagate laterally up to 30 m; whereas, low-magnitude deformation vectors extend about 25 m toward the roof and 20 m toward the floor. The vertical tensional displacement, which is concentrated in the floor and the left and right hand sides of the roof, propagates about 30 m on both sides and about 22 m in the floor. From these

  14. THE OHIO RIVER VALLEY CO2 STORAGE PROJECT - PRELIMINARY ASSESSMENT OF DEEP SALINE RESERVOIRS AND COAL SEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. Mudd; Howard Johnson; Charles Christopher; T.S. Ramakrishnan, Ph.D.

    2003-08-01

    This report describes the geologic setting for the Deep Saline Reservoirs and Coal Seams in the Ohio River Valley CO{sub 2} Storage Project area. The object of the current project is to site and design a CO{sub 2} injection facility. A location near New Haven, WV, has been selected for the project. To assess geologic storage reservoirs at the site, regional and site-specific geology were reviewed. Geologic reports, deep well logs, hydraulic tests, and geologic maps were reviewed for the area. Only one well within 25 miles of the site penetrates the deeper sedimentary rocks, so there is a large amount of uncertainty regarding the deep geology at the site. New Haven is located along the Ohio River on the border of West Virginia and Ohio. Topography in the area is flat in the river valley but rugged away from the Ohio River floodplain. The Ohio River Valley incises 50-100 ft into bedrock in the area. The area of interest lies within the Appalachian Plateau, on the western edge of the Appalachian Mountain chain. Within the Appalachian Basin, sedimentary rocks are 3,000 to 20,000 ft deep and slope toward the southeast. The rock formations consist of alternating layers of shale, limestone, dolomite, and sandstone overlying dense metamorphic continental shield rocks. The Rome Trough is the major structural feature in the area, and there may be some faults associated with the trough in the Ohio-West Virginia Hinge Zone. The area has a low earthquake hazard with few historical earthquakes. Target injection reservoirs include the basal sandstone/Lower Maryville and the Rose Run Sandstone. The basal sandstone is an informal name for sandstones that overlie metamorphic shield rock. Regional geology indicates that the unit is at a depth of approximately 9,100 ft below the surface at the project site and associated with the Maryville Formation. Overall thickness appears to be 50-100 ft. The Rose Run Sandstone is another potential reservoir. The unit is located approximately 1

  15. Coal Facies Characteristics of No.5 Coal Seam in Baidong Mine Area,Datong Coalfield%大同煤田白洞矿区5号煤层煤相特征

    Institute of Scientific and Technical Information of China (English)

    刘东娜; 周安朝; 马美玲

    2011-01-01

    Methods of optical microscope, X-ray fluorescence spectrometry (XFS) and inductively coupled plasma mass spectrometry (ICP-MS) have been used to determine macrolithotype and microlithotype of coal, geochemical parameters of the No.5 coal seam in the Taiyuan Formation, Tashan minefield, Datong coalfield; coal petrology, geochemical and coal facies characteristics discussed; and coal seam primary coal-forming peat bog environment and evolutionary pattern systematically analyzed as well. The results have demonstrated that: No.5 coal seam has four facies types, namely limnetic facies, peat bog facies, humid and rather dry forest-swamp facies, correspondingly shown as lacus, back-barrier lagoon, upper delta plain and flood basin coal-bearing systems characteristics.From bottom to top, coal seams show 5 distinct sedimentary cyclic rhythms, correspondingly environment aqueous media vary from oceanic-continental, brine-fresh water alternatively. Accordingly, a set of mainly terrestrial and transitional marine to limnic facies coal-forming peat bog environment formed, and gradually evolved from marine, marine-limnic to terrestrial facies.%采用光学显微镜、X射线荧光光谱(XFS)和电感耦合等离子体质谱(ICP-MS)等方法测定了大同煤田塔山井田太原组5号煤的宏观煤岩类型、显微煤岩类型和地球化学参数,探讨了煤的煤岩学、煤地球化学及煤相特征,系统地分析了煤层的原始成煤泥炭沼泽环境及演化规律.研究结果表明,5号煤层有4种煤相类型,即湖沼相、泥炭沼泽相、潮湿森林沼泽相和较干燥森林沼泽相,相应表现为湖泊、障壁岛后潟湖、上三角洲平原和洪泛盆地含煤沉积体系特征.煤层自下而上存在5次比较明显的沉积旋回韵律,与之相随的水介质环境也发生了相应的海陆、咸水、淡水交替变化,从而形成了一套以陆相为主、海陆交互的成煤泥炭沼泽环境,沉积环境逐渐从海相、海陆过渡相向陆相演化.

  16. Analysis of US underground thin seam mining potential. Volume 1. Text. Final technical report, December 1978. [In thin seams

    Energy Technology Data Exchange (ETDEWEB)

    Pimental, R. A; Barell, D.; Fine, R. J.; Douglas, W. J.

    1979-06-01

    An analysis of the potential for US underground thin seam (< 28'') coal mining is undertaken to provide basic information for use in making a decision on further thin seam mining equipment development. The characteristics of the present low seam mines and their mining methods are determined, in order to establish baseline data against which changes in mine characteristics can be monitored as a function of time. A detailed data base of thin seam coal resources is developed through a quantitative and qualitative analysis at the bed, county and state level. By establishing present and future coal demand and relating demand to production and resources, the market for thin seam coal has been identified. No thin seam coal demand of significance is forecast before the year 2000. Current uncertainty as to coal's future does not permit market forecasts beyond the year 2000 with a sufficient level of reliability.

  17. The Rapid Disposal Technology of Yi spontaneous seam coal mine%义煤矿区极易自燃厚煤层快速治理技术

    Institute of Scientific and Technical Information of China (English)

    吕建立; 魏向志

    2011-01-01

    The five Coal mining companies under the jurisdiction of the spontaneous combustion in coal seam coal seam for easy, the spontaneous combustion is a month, the shortest is 7 days, the spontaneous combustion of coal issues have Seriously troubled company's safety. This paper studies a foam fire suppression efficient compound blasting new technology that can make full use of current effective conventional fire - fighting technology and method, and can overcome the present grouting, an inert gas, an inert gas bubbles, resistance change agent fire - extinguishing or suppression of blasting technology for insufficient. At the same time, the paper developed an efficient compound foam generated new equipment, put forward the construction technology and rapid fire drill efficient compound foam perfusion technique, constructed different needs of extinguishing fire prevention system integration of multifnnetional. Finally, we can realize the mined - out area of the coal mine with 21201 thousand high risk of compound the equal, the whole process of rapid governance fire just in seven days, which laid a foundation to prevent disaster affected area enlargement and resume production as soon as possible.%义煤集团公司下辖的五个矿所采煤层为容易自然发火煤层,自然发火期一个月,最短7天,煤炭自燃问题严重困扰着集团公司的安全生产。本文研究了高效复合泡沫灭火抑爆新技术,既能充分利用目前有效的常规防灭火技术与手段,又能克服目前注浆、惰气、惰气泡沫、阻化剂等灭火或抑爆技术的不足,并研制了产生高效复合泡沫的新装备,提出了灭火钻孔快速施工技术和高效复合泡沫灌注技术,构建了满足不同灭火需要的多功能一体化防灭火系统。以千秋矿为例,21201工作面采空区与高冒复合火区的快速治理,整个灭火过程仅用了7天时间,为防止灾害影响范围扩大化、尽快恢复生产奠定了基础。

  18. Development trends of mining technology of coal thin seam%煤矿薄煤层开采技术的发展趋势

    Institute of Scientific and Technical Information of China (English)

    杨兵

    2016-01-01

    薄煤层由于其开采厚度较小,具有煤层薄、采高低、劳动效率低;掘进率高,采掘接替紧张;煤层的厚度、角度变化大,褶曲、断层等构造,对采煤方法影响很大。薄煤层开采技术及发展趋势有爆破落煤开采技术及发展趋势,在发展多种爆破技术的同时,发展普通机械化开采技术及发展趋势。研究滚筒采煤机开采技术及发展趋势,连续采煤机开采技术及发展趋势,螺旋钻开采技术及发展趋势。%Thin seam has characteristics of thin coal seam, low mining height, low labor efficiency; drivage ratio; the thickness,anglechanges,foldsandfaultsofcoalseamshaveansignificantimpactonminingmethod.Avarietyofblasting technologies have been developed, so does the development of general mechanized mining technology. Shearer mining technology, continuous miner mining technology and twist drill mining technology were studied in this paper.

  19. Influence of reaction parameters on brown coal-polyolefinic plastic co-pyrolysis behavior

    Energy Technology Data Exchange (ETDEWEB)

    Sharypov, V.I.; Beregovtsova, N.G.; Kuznetsov, B.N. [Institute of Chemistry and Chemical Technology SB RAS, K.Marx Str. 42, 660049 Krasnoyarsk (Russian Federation); Cebolla, V.L. [Instituto de Carboquimica, CSIC, Miguel Luesma, 4, 50015 Zaragoza (Spain); Collura, S.; Finqueneisel, G.; Zimny, T.; Weber, J.V. [Laboratoire de Chimie et Applications, Universite de Metz, rue V.Demange, 57500 Saint-Avold (France)

    2007-03-15

    Co-processing of polyolefinic polymers with Kansk-Achinsk (Russia) brown coal was investigated by thermogravimetry (TG) and autoclave pyrolysis under argon and hydrogen pressure in catalytic conditions (or not). Gas chromatography-mass spectrometry (GC-MS) and high performance thin layer chromatography (HPTLC) were used to analyze the distillate products. Some synergistic effects indicate chemical interaction between the products of thermal decomposition of coal and plastic. In co-pyrolysis under H{sub 2} a significant increasing of coal conversion degree as a function of polymer amount in feedstock was found. Simultaneously the coal promoted formation of distillate products from polymers. Some alkyl aromatic and O-containing substances were detected in co-pyrolysis fraction boiling in the range 180-350 C, indicating interactions between coal and plastic. Iron containing ore materials, modified by mechanochemical treatment, demonstrated a catalytic activity in hydropyrolysis process. In catalytic conditions, increases of the mixtures conversion degree by 9-13 wt.%, of distillate fraction yields by 1.2-1.6 times and a decrease of olefins and polycyclic components were observed. (author)

  20. Influence of additives on the increase of the heating value of Bayah’s coal with upgrading brown coal (UBC) method

    Energy Technology Data Exchange (ETDEWEB)

    Heriyanto, Heri [Chemical Engineering of University Sultan AgengTirtayasa, Indonesia Email: herfais@yahoo.com (Indonesia); Widya Ernayati, K.; Umam, Chairul; Margareta, Nita

    2015-12-29

    UBC (upgrading brown coal) is a method of improving the quality of coal by using oil as an additive. Through processing in the oil media, not just the calories that increase, but there is also water repellent properties and a decrease in the tendency of spontaneous combustion of coal products produced. The results showed a decrease in the water levels of natural coal bayah reached 69%, increase in calorific value reached 21.2%. Increased caloric value and reduced water content caused by the water molecules on replacing seal the pores of coal by oil and atoms C on the oil that is bound to increase the percentage of coal carbon. As a result of this experiment is, the produced coal has better calorific value, the increasing of this new calorific value up to 23.8% with the additive waste lubricant, and the moisture content reduced up to 69.45%.

  1. Changes in brown coal structure caused by coal-solubilizing microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Schmiers, H.; Koepsel, R.; Weber, A.; Winkelhoefer, M.; Grosse, S. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Energieverfahrenstechnik und Chemieingenieurwesen

    1997-12-31

    The phenomenon of coal solubilization caused by microorganisms has been explained by various mechanisms: extraction of non-covalently bonded polar components of the coal substance by biogenic agents (chelating agents, alkaline substances) and enzyme-catalyzed cleavage of covalent bonds by extracellular enzyme systems. For this it is assumed that bond cleavage occurs on the aliphatic carbon (methylene groups, aliphatic bridges or on ester groups). As the coal has usually been treated with oxidizing agents such as H{sub 2}O{sub 2} or HNO{sub 3} before bioconversion, there is a possibility that the result of bioconversion is overlaid with the effect of the chemical treatment. We therefore studied the structural changes in the organic coal substance during pre-oxidation with H{sub 2}O{sub 2}, treatment with MnP and conversion using the fungal strains of Trichoderma and Fusarium oxysporum. (orig.)

  2. Changes in epigeic spider community in primary succession on a brown-coal dump

    Directory of Open Access Journals (Sweden)

    Pekár, Stanislav

    1997-12-01

    Full Text Available A descriptive model of primary succession of spiders on a brown-coal dump is presented. Multivariate methods (cluster analysis and detrended correspondence analysis, and community indexes were applied to evaluate changes in community composition of epigeic spiders. Two different rehabilitation age stages were investigated. The cluster analysis helped to determine a case of horizontal asynchronous succession. The DCA was able to distinguish divergent trends of succession from the initial stage. Successional trends in species replacements were observed. In all aspects of succession there was found to be directional towards a "ruderal steppe" subclimax.

  3. Property forecasting and grading of coals of deep seams in the Prokop'evsk-Kiselevo region of the Kuzbas

    Energy Technology Data Exchange (ETDEWEB)

    Stankevich, A.S.; Proskuryakov, A.E.; Raskina, E.G.

    1976-01-01

    With the aid of vitrinite reflectance and the rank progression in stratigraphic section and processing indices, correlations have been developed to predict changes in volatile matter and plastic layer thickness with depth and horizontal distance for coals in this area. The quality of the coal falls off with increasing depth. These forecasts can be used for assessing coal reserves, to determine future blending policy, for classifying mines and optimizing the exploitation of the reserves. (LTN)

  4. Sulfur emission from Victorian brown coal under pyrolysis, oxy-fuel combustion and gasification conditions.

    Science.gov (United States)

    Chen, Luguang; Bhattacharya, Sankar

    2013-02-05

    Sulfur emission from a Victorian brown coal was quantitatively determined through controlled experiments in a continuously fed drop-tube furnace under three different atmospheres: pyrolysis, oxy-fuel combustion, and carbon dioxide gasification conditions. The species measured were H(2)S, SO(2), COS, CS(2), and more importantly SO(3). The temperature (873-1273 K) and gas environment effects on the sulfur species emission were investigated. The effect of residence time on the emission of those species was also assessed under oxy-fuel condition. The emission of the sulfur species depended on the reaction environment. H(2)S, SO(2), and CS(2) are the major species during pyrolysis, oxy-fuel, and gasification. Up to 10% of coal sulfur was found to be converted to SO(3) under oxy-fuel combustion, whereas SO(3) was undetectable during pyrolysis and gasification. The trend of the experimental results was qualitatively matched by thermodynamic predictions. The residence time had little effect on the release of those species. The release of sulfur oxides, in particular both SO(2) and SO(3), is considerably high during oxy-fuel combustion even though the sulfur content in Morwell coal is only 0.80%. Therefore, for Morwell coal utilization during oxy-fuel combustion, additional sulfur removal, or polishing systems will be required in order to avoid corrosion in the boiler and in the CO(2) separation units of the CO(2) capture systems.

  5. 高压磨料射流割缝技术在“三软”不稳定煤层中的应用%Application of high pressure abrasive jet cutting technology on 'three soft' unstable coal seams

    Institute of Scientific and Technical Information of China (English)

    饶培军; 李宝玉; 毛凯昭

    2013-01-01

    In order to solve the outburst of three soft' coal seams, the paper theoretically studied the feasibility of high pressure abrasive jet in pressure relief and penetration increase, and analyzed the gas variation of flow state of the coal seam cut 7.5 m in length in combination with software RFPA2D-Flow. The results of test conducted on working face of Daping Mine showed that the high pressure water jet effectively broadened the gas relief channel, increased the tunneling velocity of single cycle, and decreased coal gas pressure and enhanced the penetration coefficient of coal seam.%为了解决“三软”煤层的突出问题,从理论上分析了高压磨料射流在卸压增透方面的可行性,并结合RFPA2D-Flow软件分析了割缝7.5 m时煤层内瓦斯压力变化和流动情况.在大平矿工作面进行的试验结果表明,高压磨料射流技术能够有效增加瓦斯释放通道,提高单循环掘进速度,降低煤体瓦斯压力,提高煤层透气性系数.

  6. Polycyclic aromatic hydrocarbons in Australian coals. I. Angularly fused pentacyclic tri- and tetraaromatic components of Victorian brown coal

    Science.gov (United States)

    Chaffee, Alan L.; Johns, R. B.

    1983-12-01

    Analysis of the tri- and tetraaromatic hydrocarbon fractions of a brown coal sample from the Latrobe Valley, Victoria, Australia indicate the predominance of pentacyclic hydroaromatic components. Many of these have not been previously reported in the literature, but are obviously diagenetically related to triterpenoids naturally occurring in the biosphere. The components whose molecular structures have been confirmed, together with those for which tentative structural assignments are given, offer strong support for a theory of progressive diagenetic aromatization of C-3 oxygenated triterpenoids, commencing from ring A. Other compounds present in smaller amounts suggest that 1,2-methyl shift reactions also occur prior to or during aromatization. There is a notable absence of polycyclic aromatic hydrocarbons (PAH's) which can be diagenetically related to the steroid or extended-side-chain hopane skeletons.

  7. The issues of the self-fill aquifer in the north Bohemian brown coal basin

    Energy Technology Data Exchange (ETDEWEB)

    Halir, J.; Zizka, L. [Brown Coal Research Inst., Most (Czech Republic)

    2010-07-01

    The brown coal basin in the Czech Republic is located in the northwestern region of the country. Mining activities in the region have led to the flooding of various underground areas. This paper described the dewatering activities conducted as a safety procedure in a mine located in the brown coal basin. Pumping stations were established in various parts of the basin to collect inflows. Average annual pumping for the stations is approximately 990,000 m{sup 3} of mine water. The deepest pumping station in the basin is 90 meters under sea level. The activities are being conducted to ensure that a self-fill system is established to create a large self-filling water horizon after mining activities have stopped. Depressions in the mine will be successively flooded to create reservoirs of self-filling water. A computerized model of the water fluctuation rates in the mine is being prepare to accurately characterize the filling process. 6 refs., 2 figs.

  8. Demineralization of Gondwana coal with Pseudomonas mendocina strain B6-1: a case study of coal from Gopinathpur top and bottom seams of Mugma mine, Dhanbad, Jharkhand (India)

    Institute of Scientific and Technical Information of China (English)

    Prakash K.Singh; Asha Lata Singh; Mahendra P.Singh; A.S.Naik; Dharmshila Singh; Spardha Rai; Aniruddha Kumar

    2016-01-01

    In the present investigation an attempt has been made to demineralize the Gondwana coal of Gopinathpur top and bottom seams of Mugma mine,Raniganj coalfield,Dhanbad with the help of Pseudomonas mendocina strain B6-1.The change in the amount of ash yield and decrease in the concentration of selected minor elements like Na,K,Mn and Ca and environmentally sensitive selected trace elements such as Cd,Pb,Se,Ni,Mn,and Zn have been studied as a function of time of bacterial treatment as well as with variation in the bacterial biomass.After 28 days of bacterial treatment there was variable amount of decrease observed in ash yield as well as in the concentration of minor and trace elements.The removal of the elements was further enhanced with the increase in the bacterial biomass from 10 to 25 mg/mL.Due to over exploitation of superior grade coals in the country,the remaining coal resources,available for current use,are inferior in grade and contain high level of impurities and there is ample scope of bio-beneficiation of these coals using bacterial biomass.

  9. Brown coal phaseout NRW. Which coal mining amounts are necessary from an energy point of view and are possible with respect to climate policy?; Braunkohleausstieg NRW. Welche Abbaumengen sind energiewirtschaftlich notwendig und klimapolitisch moeglich?

    Energy Technology Data Exchange (ETDEWEB)

    Bauknecht, Dierk; Hermann, Hauke; Ritter, David; Vogel, Moritz; Winger, Christian

    2015-04-15

    The study on the brown coal phaseout in NRW covers the following issues: scope of the study, targets on a federal level and review of actual scenario calculations; brown coal demand in Garzweiler in the different scenarios; climate policy targets in Nordrhein-Westfalen; feasibility in the frame of energy production.

  10. Formation of NH{sub 3} during the pyrolysis of a brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Li, C.Z.; Pang, Y.; Li, X.G. [Monash Univ., Clayton, Victoria (Australia). Dept. of Chemical Engineering

    1998-12-31

    Emissions of oxides of nitrogen (NO, NO{sub 2} and N{sub 2}O) from power generation using coal are an important environmental problem, contributing to the formation of photochemical smog and acid rain or to the enhancement of greenhouse effects and to the enhanced depletion of stratospheric ozone. During pyrolysis, the nitrogen in coal, as a part of coal organic matter, is converted into NOx precursors (eg. NH{sub 3}, HCN, HNCO and the nitrogen in tar and char). These NOx precursors may then be converted into either NOx or N{sub 2} during subsequent combustion or gasification/combustion. The conversion efficiency of these NOx precursors into NOx depends strongly upon the type of NOx precursor. Knowledge of the formation of these NOx precursors during pyrolysis is therefore essential for the accurate predictions of NOx emissions from large scale power plants, and therefore for the development of optimum strategies for NOx reduction. Formation of NH{sub 3} during the pyrolysis of a Victorian brown coal (Loy Yang) has been studied in a novel reactor. The experimental results obtained suggest that a considerable amount of the nitrogen in the nascent char could be converted into NH{sub 3} if the char is held at high temperatures for a long period of time. The formation of NH{sub 3} from the thermal cracking of char was seen to last for more than an hour even at temperatures as high as 700--900 C. The experimental results seem to suggest that the differences in reactor geometries would account at least partially for some of the discrepancies in the literature regarding the formation of NH{sub 3} during the pyrolysis of coals. It is thought that NH{sub 3} may be formed from the hydrogenation of the N sites in the char by the active hydrogen generated from the thermal cracking of the char.

  11. Modified Two-Step Dimethyl Ether (DME Synthesis Simulation from Indonesian Brown Coal

    Directory of Open Access Journals (Sweden)

    Dwiwahju Sasongko

    2016-08-01

    Full Text Available A theoretical study was conducted to investigate the performance of dimethyl ether (DME synthesis from coal. This paper presents a model for two-step DME synthesis from brown coal represented by the following processes: drying, gasification, water-gas reaction, acid gas removal, and DME synthesis reactions. The results of the simulation suggest that a feedstock ratio of coal : oxygen : steam of 1 : 0.13 : 0.821 produces the highest DME concentration. The water-gas reactor simulation at a temperature of 400°C and a pressure of 20 bar gave the ratio of H2/CO closest to 2, the optimal value for two-step DME synthesis. As for the DME synthesis reactor simulation, high pressure and low temperature promote a high DME concentration. It is predicted that a temperature of 300°C and a pressure of 140 bar are the optimum conditions for the DME synthesis reaction. This study also showed that the DME concentration produced by the two-step route is higher than that produced by one-step DME synthesis, implying that further improvement and research are needed to apply two-step DME synthesis to production of this liquid fuel.

  12. Fire fighting at longwall face 67 of the Stara Jama brown coal mine in Zenica

    Energy Technology Data Exchange (ETDEWEB)

    Elezovic, V.; Bijelic, V.; Slijepcevic, S.

    1984-10-01

    A case is described of fire fighting at a 100 m long fully mechanized longwall. The fire occurred in the upper end of the longwall working a 9 m thick foot slice of a 18 m thick coal seam, i.e. beneath the goaf of the roof slice which had been outmined by the same sublevel working method. The mine fire was detected by the presence of CO in the outlet stream of mine air. Operation of the longwall was continued without interruption. The longwall crew worked using respirators. In order to extinguish the fire in the goaf, the suction type ventilation for the longwall (495 m/sup 3//min) was substituted by compressive ventilation. Two blowers were used for this purpose (2x250 m/sup 3//min). The pressure of mine air prevented the outflow of CO and enabled operations at the longwall to be continued without interruption. Fire fighting lasted nearly 2 months. A 50 m long zone, endangered by the fire, was outmined.

  13. Medullosalean fusain trunk from the roof rocks of a coal seam: Insight from FTIR and NMR (Pennsylvanian Sydney Coalfield, Canada)

    Energy Technology Data Exchange (ETDEWEB)

    Zodrow, Erwin L. [Palaeobotanical Laboratory, Cape Breton University, Sydney, Nova Scotia (Canada); Mastalerz, Maria [Indiana Geological Survey, Indiana University, 611 North Walnut Grove, Bloomington, IN 47405-2208 (United States); Werner-Zwanziger, Ulrike [Department of Chemistry, Dalhousie University, Halifax, Nova Scotia (Canada); D' Angelo, Jose A. [Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales (IANIGLA), CCT-CONICET-Mendoza, Avda. Ruiz Leal s/n Parque Gral. San Martin (5500) Mendoza (Argentina); Area de Quimica, Instituto de Ciencias Basicas, Universidad Nacional de Cuyo, Centro Universitario - M5502JMA - Mendoza (Argentina)

    2010-05-01

    Reported for the first time from the Sydney Coalfield, Canada, is a fragmentary fusain (R{sub o} = 2.51%) specimen, 41 cm long, of a medullosalean trunk or massive petiole that originated from the roof rocks of the banded bituminous Hub Seam (R{sub o} {proportional_to} 0.65%). Megascopic characteristics of the flat-preserved specimen include an irregular-cracked fusain surface with secretinite-rodlet structures and sclerenchymatous strands some of which still embedded in the shaly matrix, and locally preserved vitrain (R{sub o} 0.69%). Co-occurrence with a compression flora composed virtually of only the seed-fern taxon Macroneuropteris scheuchzeri (Hoffmann) is noted. The goal of this study is to provide a framework for the phytophysicochemical taphonomic history which includes the perspective on vitrinite/fusinite relationship, formation of fusinite, and on the significance the only fusinized identifiable plant-fossil specimen in the Sydney Coalfield. We use state-of-the-art solid-state FTIR, {sup 13}C, {sup 1}H NMR CP/MAS techniques, and standard reflected-light microscopy and SEM methods as investigative tools. Results indicate that the fusinite is characterized by long and narrow xylem fibers, without fungal signals, and cell structures infilled with pyrite and carbonate. FTIR spectra of the fusinite and secretinite are similar particularly in respect to high absorbance of aromatic and low absorbance of aliphatic compounds, and absorbance of Si-O functionalities relating to kaolinite. {sup 13}C NMR experiments with direct carbon excitation quantify the aromatic to aliphatic ratio as being 20 {+-} 3:1. As part of the taphonomic history, the evidence favors a hot, > 400 C, directional surface-fueled flame palaeofire of local extent that charred trunks of growing arborescent seed ferns on only one side, and that these trunks were transported to comprise part of the roof rocks of the Hub Seam. (author)

  14. Degassification and methane drainage in thick and vertical coal seams worked by horizontal sublevel caving method; Drenaje y Desgasificacion de Grisu en Capas de Carbon Potentes y Verticales, Explotadas por subniveles Horizontales con sutiraje

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The present trend of the working in spanish coal underground mines is directed towards the utilization, if the deposit characteristics permit it, of mining method by horizontal sublevels with caving. The application of this method involves an important coal volume in specific situations inside the workings cycle (shots, roof cavings, workings beginning, etc). Therefore, those considerable quantities of coal put into circulation, joined to high firedamp concentration desorbable of coal seam, produce in a instantaneous way large volumes of firedamp in the mine atmosphere with the consequent associated risk for the mine people, the stoppage of the works and its evacuation. These aforementioned risks could be avoided, or at least decreased to a great extent, through a methane capture before its circulation in openings caused by the mining works or by draining from accumulation rooms. During the last years, basically in EU countries, some researches have been accomplished about previous Degassification and methane capture in longwall faces of horizontal seams. In these researches have been studied the methane capture both from surface and from underground. In sublevel caving workings, substantially different from longwall faces workings, the techniques and capture systems utilized in the first one are not applicable to the second. The field works and measurements of this project have been mainly carried out in two mining companies located at the north of Spain, the Mina la Camocha S. A. and the S. A. Hullera Vasco Leonesa. Many methane capture tests by means of boreholes in coal seam have been carried out to determine the influence that capture boreholes exert in degassification of coal panel. Otherwise, many firedamp drainage tests in accumulation rooms have been also carried out, and a small-scale system that makes possible the capture in safe conditions have been defined and tested. (Author)

  15. Application of Switched System of Thin Reluctance Motor in Traction Coal Seam Shearer%开关磁阻电动机在薄煤层采煤机牵引系统中的应用

    Institute of Scientific and Technical Information of China (English)

    刘文田

    2012-01-01

    In order to meet the features and performance of thin coal seam shearer, the switched reluctance motor control system is being researched, which is suitable for traction system of thin coal seam shearer. The system uses fully digital control and the CAN-bus to make double motor SRD (Synchronous Reluctance Driver), and the floor installation of patented technology. The system can meet the requirements for thin coal seam by performance test.%为满足薄煤层采煤机的特点和性能指标,研制了一种适合薄煤层采煤机行走系统的开关磁阻电动机控制系统。系统采用了全数字控制,使用CAN总线控制实现双机同步,采用专利技术的底板安装方式。该系统通过性能试验满足了薄煤层采煤机的要求。

  16. Sequestration of carbon dioxide by indirect mineralization using Victorian brown coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yong; Parikh, Vinay [Department of Chemical Engineering, Monash University, Wellington Road, Clayton, GPO Box 36, Victoria 3800 (Australia); Zhang, Lian, E-mail: lian.zhang@monash.edu [Department of Chemical Engineering, Monash University, Wellington Road, Clayton, GPO Box 36, Victoria 3800 (Australia)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer The indirect CO{sub 2} mineralization by brown coal fly ash has been tested. Black-Right-Pointing-Pointer A large CO{sub 2} capture capacity of fly ash under mild conditions was achieved. Black-Right-Pointing-Pointer The kinetic analysis confirmed a fast reaction rate with low activation energy. Black-Right-Pointing-Pointer The fly ash based capture process is highly efficient and cost-effective. - Abstract: The use of an industry waste, brown coal fly ash collected from the Latrobe Valley, Victoria, Australia, has been tested for the post-combustion CO{sub 2} capture through indirect minersalization in acetic acid leachate. Upon the initial leaching, the majority of calcium and magnesium in fly ash were dissolved into solution, the carbonation potential of which was investigated subsequently through the use of a continuously stirred high-pressure autoclave reactor and the characterization of carbonation precipitates by various facilities. A large CO{sub 2} capture capacity of fly ash under mild conditions has been confirmed. The CO{sub 2} was fixed in both carbonate precipitates and water-soluble bicarbonate, and the conversion between these two species was achievable at approximately 60 Degree-Sign C and a CO{sub 2} partial pressure above 3 bar. The kinetic analysis confirmed a fast reaction rate for the carbonation of the brown coal ash-derived leachate at a global activation energy of 12.7 kJ/mol. It is much lower than that for natural minerals and is also very close to the potassium carbonate/piperazine system. The CO{sub 2} capture capacity of this system has also proven to reach maximum 264 kg CO{sub 2}/tonne fly ash which is comparable to the natural minerals tested in the literature. As the fly ash is a valueless waste and requires no comminution prior to use, the technology developed here is highly efficient and energy-saving, the resulting carbonate products of which are invaluable for the use as additive to

  17. 东滩煤矿煤层底板岩层阻水能力试验研究%Experiment of reduction infiltration ability of rock formation under the coal seam floor at Dongtan Coal Mine

    Institute of Scientific and Technical Information of China (English)

    张维建; 张新武; 张冬

    2015-01-01

    底板岩层压水试验能够获得可靠的底板岩层阻水能力实测数据, 为深部煤层开采底板岩层阻水能力提供量化依据,对东滩煤矿深部煤层底板岩层进行压水测试,获得了大量的实测数据并依此计算出岩层的渗透系数. 试验结果表明测试底板岩层段在原始状态下的渗透性很低,阻水能力较强.研究结果可为矿区深部工作面的安全开采提供重要的参考依据.%The reliable reduction infiltration characteristics of rock mass could be obtained by the water injection experiment under the coal seem floor. The data of water injection experimnt were obtained and permeability coefficient of floor formation were deduced through water in-jection experiment at Dongtan Coal Mine. Result shows that the test rock formations are all low-permeability, which mean they have high re-duction infiltration ability. The results make a important reference for safety-mining of deep coal seam working face.

  18. Rare earth elements in germanium-bearing coal seams of the Spetsugli deposit (Primor'e Region, Russia)

    Energy Technology Data Exchange (ETDEWEB)

    Seredin, V.V. [Russian Academy of Science, Moscow (Russian Federation)

    2005-06-01

    The paper presents first data on contents of lanthanoids and yttrium in germanium-bearing beds of the Spetsugli deposit, which vary along sampled cross sections from 86 to 316 ppm. It is shown that germanium-bearing coals are strongly enriched in yttrium and heavy lanthanoids as compared with coals located beyond the zone of germanium mineralization and with germanium-bearing coals of the Lincang deposit (South China). Vertical and lateral variations in REE concentrations and in REE patterns in germanium-bearing beds located at different hypsometric levels and different distances from supposed feeding channels of germanium-bearing solutions are considered. The REE distributions through beds show no correlation between REE and Ge contents. This is explained by diverse REE sources (granites of the basement and hydrothermal solutions of two generations) and by the different age of their accumulations in beds of the Spetsugli deposit. Reconstruction of the initial REE composition in germanium-bearing solutions circulating through coal-bearing formations during the Miocene at the stage of organic matter diagenesis shows that they were characterized by low concentrations of these elements and were relatively enriched in Eu and HREE. Anomalously high REE contents established in germanium-bearing coals are of epigenetic origin and accumulated after the formation of Ge mineralization. They were deposited by metalliferous REE-enriched and Ge-free or Ge-poor solutions of volcanic origin that circulated during the Pliocene-Early Quaternary time. In this regard, the Spetsugli deposit differs notably from the Lincang Ge-bearing coal deposit (South China), where the late epigenetic ore-formation stage probably did not take place.

  19. Regional differences in the variations of the degree of gas outburst hazard for Mecsek sub-bituminous coal seams

    Energy Technology Data Exchange (ETDEWEB)

    Nemedi Varga, Z.

    1987-01-01

    In the collieries of the Mecsek Mountains (South Hungary) in which the sub-bituminous coal is exploited, coal and gas outbursts as well as gas outbursts have been recorded in the Pecs-area since 1984, in the Szaszvar area since 1902, and nowadays in the Komlo-area since 1964. Concerning the degree of gas outbursts hazard, the differences between the Pecs and Komlo areas cannot be explained by the differences in facies, by structural differences and by the frequency of occurrence of igneous rocks. The conditions of coalification seem to be responsible for these differences. In this respect the significance of the so-called second phase coalification is emphasized.

  20. The mechanism and field test of permeability improvement by hydraulic flushing in three-soft and single coal seam%“三软”单一煤层水力冲孔卸压增透机理及现场试验

    Institute of Scientific and Technical Information of China (English)

    冯文军; 苏现波; 王建伟; 秦俊宾; 李贤忠

    2015-01-01

    Hydraulic flushing is the most effective way for high-efficient extraction in three-soft coal seam. In this paper, the mechanism was studied by laboratory experiment, theoretical analysis and field test for pressure relief and permeability improvement in three-soft coal seam after hydraulic flushing. The coupling experiment of stress and strain-coal structure-permeability revealed the evolution of permeability along with the change of the structure and stress, and found that permeability of soft coal was improved on a large scale after pressure relief. Based on Hoek-Brown criterion theory, the numerical simulation results show that the relief range increased significantly af-ter hydraulic flushing in coal. The hydraulic flushing tests using self-developed machine for gas drainage borehole in 21141 floor drainage tunnel of Daping Mine shows, the machine made hydraulic flushing more secure and effi-cient, and made it possible to repair the old drainage borehole . The field tests fully tested the reliability of the equipment and the accuracy of the above theoretical analysis, and improved the extraction efficiency significantly.%水力冲孔是实现“三软”煤层瓦斯高效抽采的有效途径之一。通过应力应变–煤体结构–渗透率的耦合实验,揭示了“三软”煤层渗透率随煤体结构和应力变化的演化规律,发现软煤在卸压后渗透率得到大规模提升。以Hoek-Brown准则为理论依据,通过数值模拟,发现水力冲孔出煤后的卸压增透范围显著增加。采用自主研发的“瓦斯抽采孔水力作业机”,在郑煤集团大平煤矿21141底板抽放巷进行了水力冲孔试验,使得水力冲孔更加安全、高效,并使得老孔的修复成为现实。现场试验充分检验了装备的可靠性和理论分析的准确性,显著提高了煤层瓦斯的抽采效率。

  1. INFLUENCE OF SATURATION PERIOD ON BURSTING LIABILITY INDICES FOR COAL SEAM #2 IN QIANQIU COAL MINE%饱水时间对千秋煤矿2#煤层冲击倾向性指标的影响

    Institute of Scientific and Technical Information of China (English)

    苏承东; 翟新献; 魏向志; 李宝富

    2014-01-01

    为分析饱水时间对煤体的力学性质与冲击倾向性指标的影响,对千秋煤矿2#煤层自然和饱水7~28 d处理后煤样,在RMT-150B岩石力学试验系统进行冲击倾向性指标测定。结果表明:在自然与饱水状态下,煤样的抗压强度与弹性模量、峰前积蓄能量和冲击能量指数均成正相关。饱水煤样的抗压强度、弹性模量、冲击能量指数以及峰前积蓄能量均有不同程度降低。饱水7~10 d后煤的力学性质和冲击倾向性指标变化显著,而后有所减缓。在自然含水状态下,2#煤层属于中等冲击类(II类),饱水7~28 d后2#煤层的冲击倾向性指标有较大降低,由中等冲击类变为弱冲击类(弱II类);建议千秋煤矿采煤工作面注水超前时间7~10 d,超前距离约30 m为宜。%To analyze the influence of saturation period on the mechanical properties and bursting liability indices of coal mass,the bursting liability indices were tested on the specimens of coal seam #2 in Qianqiu coal mine with natural water content and saturation for 7-28 d,respectively. The results show that,under natural and saturation states,the elastic modulus,impact energy index and pre-peak accumulated energy of the coal specimens are all positively correlated with the compression strength. Water saturation of the coal specimens can decrease their compression strength,elastic modulus,impact energy index and pre-peak accumulated energy in different degrees. The saturation period of 7-10 d for the coal specimens has a significant effect on their mechanical properties and bursting liability indices;after then,the influence degree would decrease. Under natural state,the bursting liability of coal seam #2 belongs to moderate impact type(type II). After the saturation period of 7-28 d,the bursting liability index decreases obviously,and becomes weak impact type(weak type II). Therefore,it is suggested that the water should be injected about 7-10 d

  2. Improving adsorption properties of semicoke from power and industrial processing of Kansk-Achinsk brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Koz' min, G.V.; Lozhaeva, V.I.; Kim, S.T.; Kalyuzhnyi, V.V.; Nikolaeva, V.A.

    1981-09-01

    Possibility is investigated of improving adsorption properties of semicoke obtained by thermocontact coking from Irsha-Borodinsk brown coal in order to use it for cleaning industrial waste water. Parameters of the porous structures, physical, chemical and adsorption properties of the semicoke are given after subjection to progressive activation by steam at 500-850 C with combustion losses of 11-48 percent. Analysis of the parameters of the porous structure showed that the total volume of micro and mezopores increased from 135 x 10 /SUP/-/SUP/6 to 779 x 10 /SUP/-/SUP/6 m/SUP/3/kg. This is mainly due to the increase in mezopores. Maximum adsorption of iodine is obtained from semicoke activated at a combustion loss of 11 percent. (4 refs.) (In Russian)

  3. Transformation of chlorine in NaCl-loaded Victorian brown coal during the gasification in steam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu; Mohammad Asadullah; Rosalie Hocking; LIN Jian-ying; LI Chun-zhu

    2012-01-01

    This study is to examine the changes in Cl volatilizations and chemical forms in NaCl-loaded Victorian brown coal during gasification in steam at 800 ℃ using Cl K-edge X-ray absorption near-edge structure (XANES) spectroscopy.The char samples were prepared in a novel one-stage fluidised-bed/fixed-bed quartz reactor at a fast heating rate.The samples were then collected and sealed in an argon-filled bag in order to minimise possible oxidation of char and Cl by air prior to analysis by XANES.Char-steam reactions were found to significantly affect the transformation of Cl,including the possible formation of chlorine-containing organic structures.On the other hand,volatile-char interactions during the gasificauon appeared to enhance the Cl retention and prevent the formation of organic chlorine compounds in chars.

  4. Sequestration of carbon dioxide by indirect mineralization using Victorian brown coal fly ash.

    Science.gov (United States)

    Sun, Yong; Parikh, Vinay; Zhang, Lian

    2012-03-30

    The use of an industry waste, brown coal fly ash collected from the Latrobe Valley, Victoria, Australia, has been tested for the post-combustion CO(2) capture through indirect minersalization in acetic acid leachate. Upon the initial leaching, the majority of calcium and magnesium in fly ash were dissolved into solution, the carbonation potential of which was investigated subsequently through the use of a continuously stirred high-pressure autoclave reactor and the characterization of carbonation precipitates by various facilities. A large CO(2) capture capacity of fly ash under mild conditions has been confirmed. The CO(2) was fixed in both carbonate precipitates and water-soluble bicarbonate, and the conversion between these two species was achievable at approximately 60°C and a CO(2) partial pressure above 3 bar. The kinetic analysis confirmed a fast reaction rate for the carbonation of the brown coal ash-derived leachate at a global activation energy of 12.7 kJ/mol. It is much lower than that for natural minerals and is also very close to the potassium carbonate/piperazine system. The CO(2) capture capacity of this system has also proven to reach maximum 264 kg CO(2)/ton fly ash which is comparable to the natural minerals tested in the literature. As the fly ash is a valueless waste and requires no comminution prior to use, the technology developed here is highly efficient and energy-saving, the resulting carbonate products of which are invaluable for the use as additive to cement and in the paper and pulp industry.

  5. 含夹矸煤层槽波频散特性及其影响因素分析%Channel Wave Dispersion Features in Coal Seam with Gangue and Its Impacting Factors

    Institute of Scientific and Technical Information of China (English)

    荣晓伟

    2015-01-01

    槽波地震勘探是常用的井下物探技术,为达到预测煤层夹矸结构的目的,依据弹性波理论,推导了含夹矸煤层的勒夫型槽波频散方程,在此基础上,分析了夹矸的结构和物性变化对槽波频散特性的影响.研究表明槽波频散特性受夹矸厚度、位置以及速度变化的影响较大:夹矸厚度越大,夹矸距离煤层中心位置越近,夹矸速度越大,勒夫型槽波的速度就越大,埃里相特征也就越不明显.%The In-seam seismic prospecting is a commonly used underground geophysical prospecting technology. To accomplish the mission of coal seam gangue structure prediction, based on elastic wave theory has deducted a Love mode channel wave dispersion equation for coal seams with gangue. On this basis, impacting from gangue structure and physical property variation on channel wave dispersion features analyzed. The study has shown that the channel wave dispersion features have largely impacted by gangue thick-ness, position and velocity variation. The larger the gangue thickness, the nearer the gangue apart from coal seam center and the larger the velocity in gangue can make the larger Love mode channel wave velocity and more inconspicuous Airy phase features.

  6. Three-dimensional numerical simulation of methane drainage by high-level drill holes in a lower protective coal seam with a‘‘U’’ type face

    Institute of Scientific and Technical Information of China (English)

    Xingkui Liu; Shuzhao Yang

    2014-01-01

    Different drill-hole positions may produce different drainage results in low protective coal seams. To inves-tigate this possibility, a 3D stope model is established, which covers three kinds of drill holes. The FLUENT computational fluid mechanics software is used to solve the mass, momentum and species conservation equations of the model. The spatial distributions of oxygen and methane was obtained by calculations and the drainage results of different drill-hole positions were compared. The results show that, from top to bottom, methane dilution by oxygen weakens gradually from the intake to the return side, and methane tends to float; methane and oxygen distribute horizontally. The high-level crossing holes contribute to better methane drainage and a greater level of control. Around these holes, the methane density decreases dramatically and a ‘‘half circle’’ distribution is formed. The methane density decreases on the whole, but a proportion of the methane moves back to deep into the goaf. The research findings provide theoretical grounds for methane drainage.

  7. THE NUMBERING INTERPRETATION-COMPARISON METHOD FOR SEDIMENTARY SEQUENCE OF COAL SEAMS IN LOGGING OF THE QIANBEI (NORTHERN GUIZHOU) COALFIELD%黔北煤田测井中煤层的沉积序列编号解释对比方法及应用

    Institute of Scientific and Technical Information of China (English)

    张应文; 王亮; 杨胜发

    2011-01-01

    以黔北煤田习水县双龙井田物探测井的应用为例,利用已知煤层或目的层,采用地质界线特征法、地质标志层特征法、煤层序列解释特征法、煤层层间距比较特征法等,对单条或多条物性参数曲线所表现的测井异常特征进行对比分析,总结煤层判定及煤层沉积序列编号的常用解释方法及经验,从而确定煤炭资源储量.%With geophysical logging applied at Shuanglong well field of Xishui County in the Qianbei coalfield as an example and by utilizing known coal seams or beds of interest and adopting such methods as geological boundary characteristic method, geological marked bed characteristic method, coal seam sequence interpretation characteristic method and coal seam inter-layer distance comparison characteristic method, the authors made a comparative analysis of logging anomaly characteristics revealed along a single curve or multiple curves of physical parameters and summed up common interpretation methods and experience obtained in coal seam judgment and coal seam sedimentary sequence numbering so as to determine coal resource reserves.

  8. Numerical simulation of coal body stress at coal seam with large inclined angle in Changgouyu%长沟峪煤矿大倾角煤层开采煤体应力数值模拟

    Institute of Scientific and Technical Information of China (English)

    孙广义; 张永彬; 于涛

    2011-01-01

    This papar is an attempt to investigate the regularity of stress distribution of the coal body at steeply dipping coal seam, by using ANSYS FEM software to simulate the stress characteristics of the coal body at -140 m level wall type working face in north fourth slot of Changgouyu mine. The results show that coal body in front of the working face has the maximum stress concentration factor of 1.92, the working face of lower part is exposed to a higher stress concentration factor, and the maximum stress varying from 4.71 Mpa to 5.12 Mpa occurs between 20 m and 24 m in the lower part of the working face. The study provides theoretical supports for safety production and support design of working face.%研究大倾角煤层开采煤体应力分布规律,应用ANSYS有限元软件对长沟峪煤矿-140m水平北-北4槽壁式工作面开采煤体应力进行数值模拟.结果表明,工作面前方煤体最大应力集中系数为1.92;工作面下部煤体的应力集中系数高于上部;煤体最大应力值介于4.71~5.12 MPa之间,发生在工作面下部20~24m范围内.该研究为工作面安全生产与支护设计提供了依据.

  9. 全烃曲线在判别煤层气井煤厚中的应用%Application of Total Hydrocarbon Curves in CBM Well Coal Seam Thickness Identification

    Institute of Scientific and Technical Information of China (English)

    单元伟; 庞涛

    2015-01-01

    During the CBM exploration, coal core data is essential in CBM potential evaluation. Thus in CBM well logging, to exactly de⁃termine coal seam position and thickness is the element task. Studies have shown, under the complex geological condition and difficult drilling situation, the total hydrocarbon curves have higher accuracy in coal seam verification. Taking the coal seam identification in 640m~645m sector of well V1 in Wangpo, Shanxi as an example, the coal seam thickness from total carbon curve interpretation is 3.8m, that is 0.2m less than well logging interpreted 4.0m, 0.1m more than geological interpreted 3.7m. Comparing with the interpreted result of 4.6m before the total hydrocarbon curve correction, the corrected result is more reliable.%在煤层气勘探中,煤心数据是评价煤层气潜力的重要指标,因此,在煤层气录井中,卡准煤层位置、计算煤层厚度是煤层气测井工作中的一项基础工作。有研究表明,在地质条件复杂及钻井困难的环境下,全烃曲线对煤层的识别具有较高的准确性。以山西王坡V1井640~645m井段煤层判识为例,其全烃解释厚度为3.8m,与测井解释的4.0m相差0.2,与地质解释的3.7m相差0.1m,与全烃曲线校正前4.6m的解释结果比较,校正后的全烃曲线解释成果比较可靠。

  10. 瓦斯抽放煤层增透深孔聚能爆破钻孔参数%Drilling parameters of deep-hole cumulative blasting to improve coal seam permeability in gas drainage

    Institute of Scientific and Technical Information of China (English)

    郭德勇; 吕鹏飞; 单智勇; 谢安

    2013-01-01

    以焦作煤业集团九里山矿煤层深孔聚能爆破试验为基础,利用数值模拟分析了爆破煤体应力变化规律,发现聚能爆破效应导致应力峰值增大,扩大了煤体裂隙区范围.同时对聚能爆破钻孔参数进行优化,确定了合理的炮孔直径、爆破孔间距、爆破孔与邻近抽放孔及煤层顶底板间距.现场试验结果表明:优化的钻孔参数不仅使聚能爆破增透效果显著而且保证了爆破过程的安全.%Based on coal seam deep-hole cumulative blasting experiments in Jiulishan Coal Mine of Jiaozuo Coal Group, the law of stress change in a blasting coal body was analyzed by numerical simulation. It is found that cumulative blasting effect leads to the increase of peak stress and enlarges the crack zone range of the coal body. Drilling parameters for cumulative blasting, such as blast hole diameter, blast hole spacing, distance between the blast hole and the adjacent gas drainage hole, and distance from the blast hole to the coal seam roof and floor, were determined by optimization. Field experimental results show that after using these optimized drilling parameters the cumulative blasting not only gets remarkable permeability increasing effect but also ensures blasting safety.

  11. analysis on coal characteristics of late Paleozoic coal seam and its Utilization in shangzhe area of henan%河南省商柘一带晚古生代煤层煤质特征与利用方向浅析

    Institute of Scientific and Technical Information of China (English)

    何新礼; 王山东; 燕婷; 丁红芳; 王朝晖

    2014-01-01

    河南省商柘一带隐伏有丰富的煤炭资源,成煤时代为晚古生代,含煤地层为二叠系下统山西组的二煤组和下石盒子组的三煤组,其中二11、二12煤层是本区的主要可采煤层,厚度分别为1.55~3.20 m,埋深790~2670 m,属较稳定煤层,煤类主要为贫煤,含少量焦煤和瘦煤,低磷分、特低氯、一级含砷煤;焦煤为特低磷分、特低氯、一级含砷,视密度1.37~1.45 t/m3。宏观煤岩类型以光亮型为主,变质阶段属Ⅴ、Ⅵ、Ⅶ、Ⅷ、Ⅸ,特高热值-高热值煤,不黏结-强黏结,较高-高软化温度灰,可用于动力用煤或民用燃料以及炼焦用煤。%there are rich hidden coal resources in the shangzhe area of henan Province. the coal forming time is the late Pleistocene. coal-bearing strata are ermei group of lower permian shanxi group and sanmei group of lower shihezi group, among which two 11 and two 12 coal seam are the main of the coal seams in the area, whose thickness were is 1.55 ~ 3.20m and depth is 790 ~ 2670m. it is a relatively stable coal seam. the coal type is mainly lean coal, containing a small amount of coking coal and meagre coal. it is low phosphorus, specially low chloride and one class arsenic-bearing coal. apparent density is 1.37 ~ 1.45 t/m3. Bright type is the main type at the types of macroscopic coal petrography. Metamorphic stage belongs to V, Vi, Vii, Viii, iX, high calorific value - Particularly high calorific value coal, no adhesion - strong adhesive, and relatively high -high softening temperature of gray. it can be used as civil fuel and coking coal or coal for power.

  12. Groundwater methane in relation to oil and gas development and shallow coal seams in the Denver-Julesburg Basin of Colorado

    Science.gov (United States)

    Sherwood, Owen A.; Rogers, Jessica D.; Lackey, Greg; Burke, Troy L.; Osborn, Stephen G.; Ryan, Joseph N.

    2016-01-01

    Unconventional oil and gas development has generated intense public concerns about potential impacts to groundwater quality. Specific pathways of contamination have been identified; however, overall rates of contamination remain ambiguous. We used an archive of geochemical data collected from 1988 to 2014 to determine the sources and occurrence of groundwater methane in the Denver-Julesburg Basin of northeastern Colorado. This 60,000-km2 region has a 60-y-long history of hydraulic fracturing, with horizontal drilling and high-volume hydraulic fracturing beginning in 2010. Of 924 sampled water wells in the basin, dissolved methane was detected in 593 wells at depths of 20–190 m. Based on carbon and hydrogen stable isotopes and gas molecular ratios, most of this methane was microbially generated, likely within shallow coal seams. A total of 42 water wells contained thermogenic stray gas originating from underlying oil and gas producing formations. Inadequate surface casing and leaks in production casing and wellhead seals in older, vertical oil and gas wells were identified as stray gas migration pathways. The rate of oil and gas wellbore failure was estimated as 0.06% of the 54,000 oil and gas wells in the basin (lower estimate) to 0.15% of the 20,700 wells in the area where stray gas contamination occurred (upper estimate) and has remained steady at about two cases per year since 2001. These results show that wellbore barrier failure, not high-volume hydraulic fracturing in horizontal wells, is the main cause of thermogenic stray gas migration in this oil- and gas-producing basin. PMID:27402747

  13. Groundwater methane in relation to oil and gas development and shallow coal seams in the Denver-Julesburg Basin of Colorado.

    Science.gov (United States)

    Sherwood, Owen A; Rogers, Jessica D; Lackey, Greg; Burke, Troy L; Osborn, Stephen G; Ryan, Joseph N

    2016-07-26

    Unconventional oil and gas development has generated intense public concerns about potential impacts to groundwater quality. Specific pathways of contamination have been identified; however, overall rates of contamination remain ambiguous. We used an archive of geochemical data collected from 1988 to 2014 to determine the sources and occurrence of groundwater methane in the Denver-Julesburg Basin of northeastern Colorado. This 60,000-km(2) region has a 60-y-long history of hydraulic fracturing, with horizontal drilling and high-volume hydraulic fracturing beginning in 2010. Of 924 sampled water wells in the basin, dissolved methane was detected in 593 wells at depths of 20-190 m. Based on carbon and hydrogen stable isotopes and gas molecular ratios, most of this methane was microbially generated, likely within shallow coal seams. A total of 42 water wells contained thermogenic stray gas originating from underlying oil and gas producing formations. Inadequate surface casing and leaks in production casing and wellhead seals in older, vertical oil and gas wells were identified as stray gas migration pathways. The rate of oil and gas wellbore failure was estimated as 0.06% of the 54,000 oil and gas wells in the basin (lower estimate) to 0.15% of the 20,700 wells in the area where stray gas contamination occurred (upper estimate) and has remained steady at about two cases per year since 2001. These results show that wellbore barrier failure, not high-volume hydraulic fracturing in horizontal wells, is the main cause of thermogenic stray gas migration in this oil- and gas-producing basin.

  14. TECHNOLOGY AND EFFICIENCY IN USAGE OF BROWN COAL ASH FOR CEMENT AND CONCRETE MIXTURES AT THE LELCHITSKY DEPOSIT

    Directory of Open Access Journals (Sweden)

    G. D. Lyahevich

    2017-01-01

    Full Text Available Modern visions on the role of high-dispersity additives in concrete mixtures reflect a positive effect of optimal amount of ash left after combustion of solid fuel on structure and physico-mechanical characteristics of cement compositions: hardening of contact zone between cement stone and aggregates with formation of “binder – aggregate” clusters due to high surface energy of aggregate particles; reduction of total cement stone porosity in concrete while increasing volumetric concentration and aggregate dispersion; binding of calcium hydroxide by amorphized silicon of pozzolanic aggregates; increase in pozzolanic aggregate activity with its fine grinding, etc. Experimental investigations have ascertained that usage of portland cement clinker ash samples left after brown coal burning at the Lelchitsky deposit contributed to an increase of cement working life and activity. Concrete samples have been obtained that have improved physico-mechanical properties owing to introduction the following components in their composition: 2–14 % (of cement mass of ash left after brown coal burning and 1.6–2.1 % of sodium salt that is a condensation product of sulfur oxidate in aromatic hydrocarbons with formaldehyde. Efficiency of the executed work has been proved by solution of the problems pertaining to an increase of neat cement working life, cement activity, concrete strength. The paper also considers no less important problem concerning protection of the environment from contamination with ash left after burning of high-ash brown coal

  15. 浅埋煤层开采的矿井水来源判别%Source Discrimination of Mine Water from Shallow Buried Coal Seams Mining

    Institute of Scientific and Technical Information of China (English)

    申涛; 马雄德; 戴国锋

    2011-01-01

    以陕北侏罗纪煤田凉水井煤矿为例,研究了浅埋煤层开采涌水量规律,根据煤矿井下水样的氢氧同位素构成,计算了矿井水的来源.该区矿井水接受风化基岩裂隙承压水和萨拉乌苏组潜水的补给,矿井水8D为-70‰,裂隙水8D为-80‰,萨拉乌苏组潜水8D为-67.46‰,由此可以计算出矿井水的补给来源主要是萨拉乌苏组地下水,萨拉乌苏组潜水补给占79.74%,基岩裂隙水补给占20.26%,据此提出该区保水采煤重点是保护萨拉乌苏组地下水含水结构的稳定性.%Taking the liangshuijing coalmine in the northern Shaanxi Jurassic coalfield as an example, studied the regular pattern of water inflow during shallow buried coal seams mining. Based on hydrogen and oxygen isotopic composition of water samples from coalmine underground, discriminated mine water source. The mine water in the area accepts recharges from weathered bedrock fissure confined water and Xar Us Formation phreatic water. The 8D of mine water is -70%0, fissure water -80%o and phreatic water -67.46%0, thus the main recharging source of mine water is from the Xar Us Formation groundwater can be calculated, the percent sharing of phreatic water is 79.74%, bedrock fissure water 20.26%. In view of the above, the emphasis on water conservation coal mining is to protect stability of Xar Us Formation water-bearing structure.

  16. Study on Influence of Coal Seam Water Infusion Pressure upon Infusion Effect%煤层注水压力对注水效果的影响研究

    Institute of Scientific and Technical Information of China (English)

    骆大勇

    2014-01-01

    分析了注水压力在煤层注水中的作用,对试验煤矿掘进工作面煤层注水进行了数值模拟,得出煤层注水压力与压裂过程中煤体破裂程度之间的变化关系。运用模拟结果对试验煤矿工作面的注水压力进行优化,取得了较好的效果。为选择适当的煤层注水压力提供了一种方法。%In this paper, analysis was made on effect of water pressure in coal seam water infusion, numerical simulation was carried out on the seam water infusion in a heading face in the experimental mine, and the variation relation between the water infusion pressure and the coal breaking degree in the fracturing process was obtained. The simulated results were used to optimize the water infusion pressure in the coal face of the mine, better effect was achieved. This thus provided a method for the selection of the appropriate infusion pressure.

  17. 浅析屯兰煤矿煤层瓦斯含量及其影响因素%Brief Discussion on Content and Influencing Factor of Gas Content in Coal Seam of Tunlan Colliery

    Institute of Scientific and Technical Information of China (English)

    王俊芳

    2011-01-01

    The important precondition of effectively preventing potential safety concerns. In this paper, the author analyzed content and regularities of distribution of gas content in coal seam from aspects of burial depth of coal seam, metamorphic grade, surrounding rock condition, geologic structure and groundwater, which provide important technical data for coal mine safety.%掌握煤矿煤层的瓦斯含量与分布规律及其影响因素,是有效防治煤矿安全生产的重要前提。从煤层埋藏深度、煤的变质程度、围岩条件、地质构造、地下水的活动等方面,分析了煤层瓦斯含量及其分布规律,为煤矿安全防治工作提供了重要的技术指标。

  18. 沁水煤田流渠勘查区煤层赋存特征%Occurrence Features of Coal Seam of Flow Channel Exploration Area of Qinshui Coalfield

    Institute of Scientific and Technical Information of China (English)

    李重阳

    2014-01-01

    沁水煤田流渠勘查区构造简单,地层总体产状为走向北东,倾向北西的单斜。勘查区东部外侧有一小型背斜,背斜影响使范围内地层产状发生变换和地层产状的变换,导致各煤层底板标高及煤层间间距发生变换。%The flow channel exploration area of Qinshui coa-lfield has the advantages of simple structure;the coal strip ro-ughly stretches from the Northern East with monoclinic ten-dency towards Northern West. At the east lateral part of the exploration area is a small anticline which makes the change of the coal strip form in its governing scope, leading to the cha-nge of the elevation height of the coal seam floor and the seam spacing.

  19. Geothermal, Geochemical and Geomagnetic Mapping Of the Burning Coal Seam in Fire- Zone 18 of the Coal Mining Area Wuda, Inner Mongolia, PR China.

    Science.gov (United States)

    Kessels, W.; Han, J.; Halisch, M.; Lindner, H.; Rueter, H.; Wuttke, M. W.

    2008-12-01

    Spontaneous combustion of coal has become a world wide problem caused by and affecting technical operations in coal mining areas. The localization of the burning centre is a prerequisite for any planning of fire fighting operations. In the German - Chinese coal fire project sponsored by the German Ministry of Science and Technologies (Grant No. 0330490K) the so called fire zone 18 of the coal mining area of Wuda (InnerMongolia, PR China) serves as a test area for geophysical measurements. For the geothermal and geochemical mapping 25 up to 1m deep boreholes with a diameter of approx. 30 mm are distributed over the particular fire-zone with an extension of 320 × 180 m2. To avoid the highly dynamic gas flow processes in fire induced fractures caused by weather conditions, all boreholes were situated in the undisturbed rock compartments. In these boreholes, plastic tubes of 12 mm diameter provide access to the borehole ground filled with highly permeable gravel. The boreholes are otherwise sealed to the atmosphere by clay. The geothermal observations consist of measurements of temperature profiles in the boreholes and thermal conductivity measurement on rock samples in the lab. For depths greater then 0.2 m diurnal variations in the temperature gradient were neglected. The derived heat flow with maximum values of 80 W/m2 is more then three orders of magnitude higher than the natural undisturbed heat flow. The high heat flow suggests that the dominant heat transport is gas convection through the system of porous rock and fractures. Any temperature anomaly caused by the burning coal in a depth of more than 18 m would need years to reach the surface by a heat transport restricted to conduction. The geochemical soil gas probing is performed by gas extraction from the boreholes. Measured are the concentrations of O2, CO, CO2, H2S and CH4. The O2 deficit in the soil air and the concentrations of the other combustion products compared to the concentrations in the free

  20. Detection technique of transmission in-seam wave for concealed fault in working face of underground coal mine%煤矿井下工作面内隐伏断层透射槽波探测技术

    Institute of Scientific and Technical Information of China (English)

    李刚

    2016-01-01

    The concealed fault influences not only the highly efficient extraction of coal resources, but also brings potential threat for safe production in coal mine. The paper conducted in-seam seismic numeric simulation for the concealed fault in a working face, verified the feasibility of the detection of the consealed fault by transmission method. Then the holographic observation was used to conduct transmission in-seam wave detection in working face 45301, through analysis of frequence dispersion and CT imaging, the distribution of the conceraled faults in working face was found out. The comparison of the detection and the mining show that the transmission in-seam detection tehnique can efficiently detect the consealed faults in working face, provide efficient technical support for safe mining in coal mine.%工作面内隐伏断层不仅严重影响煤炭资源的高效回采,而且给煤矿安全生产带来了潜在威胁。通过对工作面内隐伏断层的槽波地震数值模拟,证实了槽波透射法探测隐伏断层的可行性。采用全息观测方式对45301工作面进行了透射槽波探测,通过频散分析及 CT 成像,查明了工作面隐伏断层分布情况。探采对比表明,透射槽波探测技术能够有效探查工作面内部的隐伏断层,为煤矿安全开采提供有效技术支撑。

  1. 基于COMOSOL的顺层钻孔有效抽采半径的数值模拟%Numerical Simulation on Effective Drainage Radius of Drill Hole Along Coal Seam Based on COMSOL

    Institute of Scientific and Technical Information of China (English)

    王兆丰; 李炎涛; 夏会辉; 谭蓉晖

    2012-01-01

    In order to accurately determine the effective drainage radius of drill hole along coal seam, according to the Darcy~ law and the law of conservation of mass as well as the theory of gas flow and occurrence, the gas flow equation of gas extraction drill hole along coal seam was established to study the flow field of coal seam gas around the drilling. Taking Qinxin mine as an example, the gas flow equation was simulated under different drainage negative - pressure and drainage time by using COMSOL software, and the reasonable drainage negative -pressure, drainage time and the effective drainage radius were determined.%为了能够准确地确定顺层瓦斯抽采钻孔的有效抽采半径,以煤层瓦斯赋存及瓦斯流动理论为基础,根据达西定律和质量守恒定律,以钻孔周围煤体瓦斯流动场为研究对象,建立了顺层瓦斯抽采钻孔的瓦斯流动方程,并以沁新煤矿为例,利用COMOSOL软件对抽采钻孔在不同的抽采负压和抽采时间下的瓦斯流动方程进行了数值模拟,确定出了合理的抽采负压、抽采时间及有效抽采半径。

  2. Chemical constituents and structural characteristic of the combined acids in brown coal resin from Chinese brown coal waxes%褐煤树脂中结合酸的化学组成与结构特征

    Institute of Scientific and Technical Information of China (English)

    李宝才; 傅家谟; 卜贻孙; 黄祖琦; 盛国英

    2001-01-01

    对云南潦浒、寻甸、吉林舒兰褐煤树脂中结合酸进行了GC-MS分析,对其化学组成及结构特征进行了对比研究.结果显示,树脂结合酸均以正构烷酸为主要成分,其分布为C12~C28,高含量的正构烷酸集中在低碳数一端.在潦浒、寻甸树脂结合酸中,C20含量最高,其次为C16,而在舒兰结合酸中,正构烷酸占绝对优势,且C16为最高含量的化合物;去氢松香酸在每个样品中含量均较低,其它三环二萜酸,如松脂酸、三达松脂酸等异构体或立体异构体含量也非常低;具有五环三萜骨架的酸性物质,在潦浒、舒兰结合酸中比较丰富,其含量超过寻甸结合酸;在低碳数一端,存在着各种支链烷酸及苯甲酸、苯酚及取代物.对比树脂烃、树脂游离酸的结果,潦浒树脂结合酸与寻甸树脂结合酸无论从组成和分布上都是极其相似的,故其原料煤成煤植物和成煤环境具有相似性,与舒兰煤之生源和环境存在着本质的差异.%The acids combined to form esters, LHZZS,XDZZS and SLZZS, the fractio ns in brown coal resins from brown coal waxes from Liaohu, Xundian (Yunnan Province) and Shulan(Jilin Province) brown coal respectively, were derived by CH 2N2 to methyl esters and their chemical constituents and structural characteristic were studied on GCMS. The experimental results demonstrate that normal fatty acids from C12 to C28are dominant in combined acid fraction, but concen trated mainly in low carbon number (C16,C18,C20,C22). Fatty acid with highest content both in LHZZS and XDZZS is eicosanoic acid, the next, hexadecanoic acid. In SLZZS, the normal fatty acids are absolutely dominant compositions, hexadecanoic acid with the highest content, the next, benzoic acid; Tricyclic diterpanoic acids and pentacyclic triterpanoic acids, such as dehydroabietic acid, pimaric acid, isopima ric acid, sandaracopimaric acid, tetrahydroabietic acid

  3. Methane production from coal seams and CO2 uptake capability of the Mecsek mountain range, Hungary; Die Methangewinnung aus Kohlefloezen und das CO{sub 2}-Aufnahmevermoegen des Mecsek-Gebirges in Ungarn

    Energy Technology Data Exchange (ETDEWEB)

    Varga, Z.N. [Univ. Miskolc (Hungary); Lakatos, I. [Forschungsinstitut der angewandten Chemie (Hungary); Foeldessy, J.; Toth, J.; Fodor, B.; Csecsei, T. [Ungarischer Geologischer Dienst, Rotaqua KFT (Hungary)

    2006-06-15

    Methane from the Mecsek mountain range coal seams is of vast economic importance. Modified geological models focusing on zones of enhanced permeability may be useful in the development of practicable winning technologies. High gas volumes are assumed in stowed material, which may be recovered by a simple technology. There is a power station in the vicinity which produces waste gases that may be used for injection, so the Mecsek region offers promising conditions for CO2 CBM production. The same power plant is also a potential consumer of the recovered methane. (orig.)

  4. 基于突变理论的煤层不连续性检测技术%Technology for detection of coal seam discontinuity based on catastrophe theory

    Institute of Scientific and Technical Information of China (English)

    于鹏飞; 董守华; 杨小慧; 薛海飞; 程彦

    2011-01-01

    通过突变理论的尖点突变模型及分析,将地震信号转化为尖点突变的标准形式.在时间域、频域计算突跳势、突跳时间等突跳参数,分析突跳参数异常,较好的反映了煤层的不连续性;比较相干、突跳理论两种技术在反映煤层不连续性上的效果,分析了各种技术的优缺点.尝试将相干属性和突跳参数属性进行融合,得到新的属性切片,很好的反映了煤层断层和裂隙富集区的分布情况.研究表明,利用突变参数进行断层的检测是可行的,突变理论将为煤层不连续性检测提供一种新的方法.%The cusp model of catastrophe theory and its expression are mentioned in this paper. The seismic record is transformed into the normal form of cusp catastrophe. Catastrophic potential, catastrophic time and so on are calculated in time domain and in frequency domain. Analysis of catastrophic anomalies can better reflect the discontinuity of coal seam. Comparing the effect of the theories of coherence and catastrophe in reflecting coal seam discontinuity, advantages and disadvantages of these two techniques were analyzed. Finally attempting to attribute catastrophe parameters with coherence and getting the new sections can reflect the distribution of zones rich in faults and fractures in coal seams. The study indicates that using catastrophe parameters to detect faults is feasible and catastrophe theory provides a new method for coal seam discontinuity detection.

  5. Material and structural characterization of alkali activated low-calcium brown coal fly ash.

    Science.gov (United States)

    Skvára, Frantisek; Kopecký, Lubomír; Smilauer, Vít; Bittnar, Zdenek

    2009-09-15

    The waste low-calcium Czech brown coal fly ash represents a considerable environmental burden due to the quantities produced and the potentially high content of leachable heavy metals. The heterogeneous microstucture of the geopolymer M(n) [-(Si-O)(z)-Al-O](n).wH(2)O, that forms during the alkaline activation, was examined by means of microcalorimetry, XRD, TGA, DSC, MIP, FTIR, NMR MAS ((29)Si, (27)Al, (23)Na), ESEM, EDS, and EBSD. The leaching of heavy metals and the evolution of compressive strength were also monitored. The analysis of raw fly ash identified a number of different morphologies, unequal distribution of elements, Fe-rich rim, high internal porosity, and minor crystalline phases of mullite and quartz. Microcalorimetry revealed exothermic reactions with dependence on the activator alkalinity. The activation energy of the geopolymerization process was determined as 86.2kJ/mol. The X-ray diffraction analysis revealed no additional crystalline phases associated with geopolymer formation. Over several weeks, the (29)Si NMR spectrum testified a high degree of polymerization and Al penetration into the SiO(4) tetrahedra. The (23)Na NMR MAS spectrum hypothesized that sodium is bound in the form of Na(H(2)O)(n) rather than Na(+), thus causing efflorescence in a moisture-gradient environment. As and Cr(6+) are weakly bonded in the geopolymer matrix, while excellent immobilization of Zn(2+), Cu(2+), Cd(2+), and Cr(3+) are reported.

  6. 近距离薄煤层条带开采引起地表变形模拟分析%Simulation Analysis of Surface Deformation by Strip Mining in the Short- Distance Thin Coal Seam

    Institute of Scientific and Technical Information of China (English)

    王传团; 潘志存; 张学豪

    2012-01-01

    近距离薄煤层条带开采是“三下”开采中控制覆岩移动变形和地表沉陷的有效方法之一,提高煤炭资源回收率,同时减少煤矿开采对矿区环境、地表破坏的影响,具有重要的理论意义和应用价值。本文采用数值模拟方法研究了近距离薄煤层条带开采引起的地表变形特征,结果表明:当采出率为50%时条带方案选取采40m留40m时最为合适。%The strip mining in short - distance thin coal seam is one of the effective methods controlling displacement deformation of overlying strata and surface subsidence in coal mining under buildings and railroads and water bodies. The method has a great theoretical significance and application value by increasing recovery rate of coal resources and cutting down the effect of coal mining on environment and surface of mining area. The numerical simulation method is adopted to study the surface deformation characteristics by the strip replacement mining in short - distance thin coal seam. Such conclusions are drawn as follows: the strip project of forty meters mining with forty meters reserving is quite suitably selected while half of mining rate.

  7. Methods and costs of thin-seam mining. Final report, 25 September 1977-24 January 1979. [Thin seam in association with a thick seam

    Energy Technology Data Exchange (ETDEWEB)

    Finch, T.E.; Fidler, E.L.

    1981-02-01

    This report defines the state of the art (circa 1978) in removing thin coal seams associated with vastly thicker seams found in the surface coal mines of the western United States. New techniques are evaluated and an innovative method and machine is proposed. Western states resource recovery regulations are addressed and representative mining operations are examined. Thin seam recovery is investigated through its effect on (1) overburden removal, (2) conventional seam extraction methods, and (3) innovative techniques. Equations and graphs are used to accommodate the variable stratigraphic positions in the mining sequence on which thin seams occur. Industrial concern and agency regulations provided the impetus for this study of total resource recovery. The results are a compendium of thin seam removal methods and costs. The work explains how the mining industry recovers thin coal seams in western surface mines where extremely thick seams naturally hold the most attention. It explains what new developments imply and where to look for new improvements and their probable adaptability.

  8. Forming the Composition of Underground Coal Gasification Products in the Simulation of Various Heat and Mass Transfer Conditions in the Coal Seam

    Directory of Open Access Journals (Sweden)

    Masanik A.S.

    2016-01-01

    Full Text Available The mathematical model describing the heat and mass transfer processes in underground coal gasification is proposed. Numerical studies have allowed to determine the composition of gases depending on the temperature, pressure products of gasification, and the composition of the heated oxidant injected. Relations the composition of the concentration of combustible gas component of the oxidant injected: dry air, a mixture of oxygen, nitrogen and water vapor in different proportions were prepared. It is found that, depending on the oxygen content in the oxidizer low-temperature gasification mode is implemented (up to 15%. At higher values of the oxygen concentration in the oxidizer the high-temperature mode is realized, in which the fuel gas output increases significantly.

  9. 平顶山矿区高突煤层立体抽放安全高效回采技术的探索与实施%Exploration and implement of the technology of stereoscopic gas drainage and safe and efficient mining for the high outburst coal seam in the Pingdingshan coal mine area

    Institute of Scientific and Technical Information of China (English)

    杨建国

    2015-01-01

    针对平顶山矿区煤层开采深度大、瓦斯含量高、突出危险性大、煤层透气性低的特点,在首山一矿探索出了大采长一面多巷立体抽放瓦斯治理格局。通过抽放巷及本煤层快速掘进,为瓦斯治理创造了时间和空间,同时利用穿层钻孔和顺层钻孔立体抽放,实现了安全高效回采。%Aiming at the features of coal seam with deep mining,high gas,greater outburst danger,low gas permeability in Pingdingshan coal mine area,the gas treatment which was stere-oscopic gas drainage in the long working face with multi-roadway was explored in the Shoushan No. 1 Coal Mine. Speedy drivage of the gas drainage roadway and the working seam roadway provides time and space for gas treatment,and the stereoscopic gas drainage by boreholes down and cross the seam reaches safe and efficient mining.

  10. Status and Outlook of Key Technology for Automation Coal Mining Face in Thin Seam%薄煤层自动化工作面关键技术现状与展望

    Institute of Scientific and Technical Information of China (English)

    田成金

    2011-01-01

    According the automatic coal mining face with a coal shearer in a thin seam and the automatic coal mining face with a coal plough in a thin seam,a brief analysis and summarization was conducted on the application status of the related automatic key technology and the restricted factors.An analysis was conducted on the coal and rock interface identification,the automatic lining technology of the coal mining face equipment,the posture detection and control technology,the plough head detection technology,the plough head control technology and other automatic mining key technology needed to be broken through in the present automatic coal mining face in China.Some technical difficulties needed to be solved in the next development of the automatic coal mining face were provided.The paper summarized the present study status of those technical difficulties and provided the further study orientation.%针对我国采煤机薄煤层自动化工作面和刨煤机薄煤层自动化工作面,就其中涉及的自动化关键技术应用现状与制约因素进行了概括性的分析与总结,对我国现阶段自动化工作面中急需突破的煤岩界面识别、工作面设备自动找直技术、姿态检测控制技术、刨头检测技术、刨头控制技术等自动化开采关键技术进行分析,提出自动化工作面下一步发展迫切需要解决的一些技术难题,总结这些技术难题的研究现状,并提出下一步的研究方向。

  11. CO2 adsorption properties of char produced from brown coal impregnated with alcohol amine solutions.

    Science.gov (United States)

    Baran, Paweł; Zarębska, Katarzyna; Czuma, Natalia

    2016-07-01

    Carbon dioxide (CO2) emission reduction is critical to mitigating climate change. Power plants for heating and industry are significant sources of CO2 emissions. There is a need for identifying and developing new, efficient methods to reduce CO2 emissions. One of the methods used is flue gas purification by CO2 capture through adsorption. This study aimed to develop CO2 adsorbent out of modified brown coal impregnated with solutions of first-, second-, and third-order amines. Low-temperature nitrogen adsorption isotherms and CO2 isotherms were measured for the prepared samples. The results of experiments unexpectedly revealed that CO2 sorption capacity decreased after impregnation. Due to lack of strait trends in CO2 sorption capacity decrease, the results were closely analyzed to find the reason for the inconsistencies. It was revealed that different amines represent different affinities for CO2 and that the size and structure of impregnating factor has influence on the CO2 sorption capacity of impregnated material. The character of a support was also noticeable as well for impregnation results as for the affinity to CO2. The influence of amine concentration used was investigated along with the comparison on how the theoretical percentage of the impregnation on the support influenced the results. The reaction mechanism of tertiary amine was taken into consideration in connection to no presence of water vapor during the experiments. Key findings were described in the work and provide a strong basis for further studies on CO2 adsorption on amine-impregnated support.

  12. A Systematic Analysis of Coal Accumulation Process

    Institute of Scientific and Technical Information of China (English)

    CHENG Aiguo

    2008-01-01

    Formation of coal seam and coal-rich zone is an integrated result of a series of factors in coal accumulation process. The coal accumulation system is an architectural aggregation of coal accumulation factors. It can be classified into 4 levels: the global coal accumulation super-system, the coal accumulation domain mega.system, the coal accumulation basin system, and the coal seam or coal seam set sub-system. The coal accumulation process is an open, dynamic, and grey system, and is meanwhile a system with such natures as aggregation, relevance, entirety, purpose-orientated, hierarchy, and environment adaptability. In this paper, we take coal accumulation process as a system to study origin of coal seam and coal-rich zone; and we will discuss a methodology of the systematic analysis of coal accumulation process. As an example, the Ordos coal basin was investigated to elucidate the application of the method of the coal accumulation system analysis.

  13. The loss of Na and Cl during the pyrolysis of a NaCl-loaded brown coal sample

    Energy Technology Data Exchange (ETDEWEB)

    Mody, D.; Li, C.Z.

    1999-07-01

    A Victorian brown coal was physically loaded with NaCl and pyrolyzed in a quartz fluidized-bed reactor. The fluidized-bed reactor was equipped with a quartz frit in the freeboard zone to enable the total devolatilization of the coal particles. The introduction of NaCl into the coal has caused only minor reductions in the weight loss. A significant amount of chlorine was volatilized during pyrolysis at temperatures as low as 200 C. At temperatures around 400--500 C where the loss of sodium was not very significant, about 70% of chlorine was volatilized from the coal particles. With the volatilization of chlorine at this temperature level, sodium must have been bonded to the char matrix. With increasing temperature, the volatilization of chlorine decreased and then increased again, whereas the volatilization of sodium increased monotonically with increasing temperature. Almost all the Na in coal could be volatilized at temperatures higher than about 800 C. These experimental results clearly indicate that chlorine and Na interacted strongly with coal/char at high temperatures. Na and Cl in the coal did not volatilize as NaCl molecules. Significant amounts of species containing a COO-group such as acetate, formate and oxalate were observed in the pyrolysis products although the exact forms of these species (i.e., as acids, salts or esters) in the pyrolysis product remain unknown. The yields of the species containing a COO-group decreased with increasing temperature, possibly due to the intensified thermal cracking reactions at high temperatures.

  14. Study on safe thickness of overlying thin bedrock in fully-mechanized top-coal caving face with thick coal seam

    Institute of Scientific and Technical Information of China (English)

    FANG Xin-qiu; HUANG Han-fu; HE Jie

    2007-01-01

    To prevent support crush, the overlying strata safe thickness and its influential elements were studied by the adoption of theoretical analysis, numerical simulation and in-situ measurement. According to the production and geological condition of first face in Sima coal mine, the results indicate that the clay contains large permissible bearing ability and has better arching force. After mining destruction, stable structure is formed in bedrock to ensure face safety. The clay thickness & bedrock thickness are the key influential elements to stable structure. The minimal bedrock thickness is about 40 m to ensure safe mining under loose surface soil condition. When surface soil contains mainly thick clay, it forms steady structure with the composition of thin bedrock, so that it can reduce minimal thickness of bedrock and to ensure safe mining. When clay thickness is 40 m, minimal bedrock thickness is 20 m. When clay thickness is 30 m, minimal bedrock thickness is 30 m. Bearing pressure peak ranges from 5 to 15 m in the front face under thin bedrock condition. The bearing pressure distribution range is 15 m. Main roof break distance is small, and initial weighting of main roof is not distinctive, while first periodic weighting of main roof is quite distinctive.

  15. The analysis of antireflection range in coal seam hydraulic fracturing%本煤层水压致裂增透范围分析

    Institute of Scientific and Technical Information of China (English)

    赵源; 曹树刚; 李勇; 覃乐

    2015-01-01

    在理论分析水压致裂起裂机理和起裂方向的基础上,应用煤岩损伤破裂过程渗流-应力耦合分析系统,对5种不同地应力条件下的本煤层水压致裂过程进行模拟,得到了煤体的起裂方向、起裂压力和扩展压力.研究发现:侧压系数λ<1时,煤体基本沿垂直方向起裂,起裂压力和扩展压力呈逐步增长的趋势;λ>1 时,煤体的起裂方向为水平,起裂压力和扩展压力表现出平缓降低的趋势;在λ=1时,运用3种屈服准则进行了对比分析,得到了不同判别准则下的最小起裂水压.通过对λ=1.2时的受力状态进行深入分析,提出了压裂增透范围为宏观裂隙区、微裂隙贯通区、微裂隙产生区(受拉区)和原生裂隙扰动区(压应力恢复区)之和;利用数值图像处理得到的增透面积增长趋势符合二次函数的关系.%Based on the theoretical analysis of crack initiation mechanism and crack direction of hy-draulic fracturing, the hydraulic fracturing process of coal seam under five different in-situ stress situa-tions has been simulated by using the seepage-stress coupling analysis system of coal and/or rock dam-age & fracture process, and hence, the crack initiation direction, initial pressure and expansion pressure have been obtained. Studies have found that, the crack direction is vertical, with the initial pressure as well as the expansion pressure presenting as gradual increasing trend when the lateral pressure coeffi-cientλ<1. When the lateral pressure coefficientλ>1, the crack direction is horizontal, with the initial pressure and the expansion pressure presenting as gradually decreasing trend. When the lateral pressure coefficientλ=1, by carrying out three different kinds of yield criterion contrastive analysis, the minimum initial pressure are respectively obtained under the different kinds of yield criterion. Through the further stress analysis, i.e., when coefficientλ=1.2, studies have proposed

  16. Characteristics of fracture development and gas extraction of a lower protected seam

    Institute of Scientific and Technical Information of China (English)

    王海锋

    2009-01-01

    To ensure the mining safety of working face in the protective seam and meanwhile extract pressure-relief gas of the lower protected seam and eliminate its outburst risk,the present study researched into fracture development of floor coal-rock mass of the protective seam and migration rule of pressure-relief gas from a protected seam so as to obtain an effective pressure- relief gas extraction method.The results show that after the upper protective seam was mined,mining-induced fracturing floor coal-rock mas...

  17. 特厚煤层大采高综放工作面覆岩上层活动规律的相似模拟研究%Analog Simulation Study on Deformation and Failure Laws of Overlying Strata of Full -mechanized Top- coal Caving Face with Large Mining Height in Extra Thick Coal Seam

    Institute of Scientific and Technical Information of China (English)

    陈义东; 李英明

    2011-01-01

    In order to know well the movement pattern of overlying strata and the distribution of abutment pressure in the fullmechanized top - coal caving face with large mining height of the 4# coal seam of which thickness is form 14 m to 20 m, in Liuhuanggou coal mine of Xinjiang Hami Coal Industry (Group)Co.Ltd, physical simulation experiment and studies were carried out.The results showed that a stable arch structure can form in overlying strata of full - mechanized top - coal caving face with large mining height of extra thick coal seam, under the stable arch structure the fractured rock beam becomes a multispan beam structure.The deformation and unstability of the structure in overlying strata of full - mechanized top - coal caving face with large mining height dominate the abutment pressure distribution and strata pressure behavior of coal mining face.%新疆哈密煤业集团硫磺沟矿4号煤层厚度为14~20m,为掌握该特厚煤层综放工作面上覆岩层活动规律以及支承压力分布特点,采用物理相似模拟方法进行了研究,研究结果表明,特厚大采高综放工作面的上位岩层可以形成稳定拱结构,而在稳定拱大结构之下,断裂岩梁形成多跨梁的结构.大采高综放采场上覆岩层的这种结构的变形和失稳将决定采场的支承压力分布和工作面的矿压显现.

  18. Late Cretaceous-Paleogene Palynostratigraphy from the Arkhara-Boguchan Brown Coal Mine of Zeya-Bureya Depression, Russia

    Institute of Scientific and Technical Information of China (English)

    Tatyana V. Kezina

    2003-01-01

    A well-preserved Late Cretaceous-Paleogene palynological flora from the middle member of the Tsagajan Formation and the upper member of the Tsagajan Formation including the Kivda Beds is reported for the first time from the Arkhara-Boguchan brown coal mine, southeastern part of the Zeya-Bureya Basin. Four palynocomplexes were established for the Cretaceous-Tertiary transition. The climate and phytocoenoses were also analyzed,based on the detailed palynological data. The results are coincident with those of mega-flora studied by Akhmetiev et al. (2002).

  19. Thirty five years of North Bohemian brown coal region after liberation of Czechoslovakia by the Soviet army

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, M.

    1980-09-01

    Problems of the North Bohemian brown coal basin are evaluated. In 35 years coal output of the region increased from 40 Mt to nearly 70 Mt in spite of deteriorating mining and geological conditions and shortages of manpower. Output increase was possible as a result of a comprehensive program of modernization and construction of new mines. The following mines are the most productive in the region: Maxim Gorkij, Most, CSA, Jan Sverma, Chabarovice, Merkur, Brezno, Vrsany. Investments in modernizing older mines and constructing new surface mines are evaluated: the investments increased from close to 800 million crowns in 1971 to over 2 billion crowns in 1979. Machines and equipment used in the North Bohemian surface mines are characterized: K 1000, K-800-B, K-300 bucket wheel excavators, D 800, DO 800 and DO 400 bucket chain excavators as well as the high capacity KU 800 bucket wheel excavator.

  20. 薄煤层泵送矸石充填开采矿压显现规律研究%Research on Strata Behavior in the Process of Gangue Backfill by Filling Pump in Thin Coal Seam

    Institute of Scientific and Technical Information of China (English)

    林惠立; 李洪; 刘庆龙

    2012-01-01

    为有力地配合北宿煤矿薄煤层泵送矸石充填开采工业性试验,更好的为今后薄煤层充填开采提供可靠依据,在C1661充填开采工作面进行了矿压观测,C1661充填开采工作面与1863采用全部垮落法开采工作面相比,顶底板移近量增大11.4%,单体支柱末阻力增大54.8%,液压切顶支架末阻力增加8.8%,支架活柱缩量增大5.7%,支护强度基本相等,来压强度减小28%,周期来压步距增大27.3%,初次来压步距增大12%。%In order to coordinate with industrial test of gangue backfill by filling pump in thin coal seam in Beisu Coal Mine, and provide a more reliable basis for fill mining in thin coal seam in the future, strata control observation was conducted in C1661 working face. And com- pared with 1863 face which was mined by caving method, convergence between roof and floor increased by 11.4%, terminal resistance of sin- gle prop increased by 54.8%, terminal resistance of hydraulic support increased by 8.8%, expansion amount of hydraulic support increased by 5.7%, ground pressure strength decreased by 5.7%, periodic weighting length increased by 27.3%, first weighting interval increased by 12%, and the strength of support was basically the same.

  1. Nitrogen oxides, sulfur trioxide, and mercury emissions during oxy-fuel fluidized bed combustion of Victorian brown coal.

    Science.gov (United States)

    Roy, Bithi; Chen, Luguang; Bhattacharya, Sankar

    2014-12-16

    This study investigates, for the first time, the NOx, N2O, SO3, and Hg emissions from combustion of a Victorian brown coal in a 10 kWth fluidized bed unit under oxy-fuel combustion conditions. Compared to air combustion, lower NOx emissions and higher N2O formation were observed in the oxy-fuel atmosphere. These NOx reduction and N2O formations were further enhanced with steam in the combustion environment. The NOx concentration level in the flue gas was within the permissible limit in coal-fired power plants in Victoria. Therefore, an additional NOx removal system will not be required using this coal. In contrast, both SO3 and gaseous mercury concentrations were considerably higher under oxy-fuel combustion compared to that in the air combustion. Around 83% of total gaseous mercury released was Hg(0), with the rest emitted as Hg(2+). Therefore, to control harmful Hg(0), a mercury removal system may need to be considered to avoid corrosion in the boiler and CO2 separation units during the oxy-fuel fluidized-bed combustion using this coal.

  2. Metallization of oxide-ore-containing wastes with the use of brown coal semicoke from Berezovsky deposit of the Kansk- Achinsk Basin

    Science.gov (United States)

    Anikin, A. E.; Galevsky, G. V.; Nozdrin, E. V.; Rudneva, V. V.; Galevsky, S. G.

    2016-09-01

    The research of the metallization process of the roll scale and sludge after gas treatment in the BOF production with the use of brown coal semicoke mined in Berezovsky field of the Kansk-Achinsk Basin was carried out. A flow diagram of “cold” briquetting using a water-soluble binder was offered. The reduction of iron from its oxide Fe2O3 with brown coal semicoke in the laboratory electric-tube furnace in the argon atmosphere was studied. The mathematical models of dependence of the metallization degree on variable factors were developed. The optimal values of technological factors and essential characteristics of the obtained metallized products were revealed.

  3. Autochthonous microbe-assisted phytoremediation of brown coal mine overburden soil

    Science.gov (United States)

    Hamidović, Saud; Teodorović, Smilja; Lalević, Blažo; Karličić, Vera; Jovanović, Ljubinko; Kiković, Dragan; Raičević, Vera

    2015-04-01

    One of the largest brown coal mines in Bosnia and Herzegovina (BiH), Kakanj, has been exploited for over a hundred years. As a consequence of decades of exploitation, severe biocenosis disturbance and degradation of the entire ecosystem have occurred, resulting in overburden soil formation. A significant challenge in remediation of degraded mining areas is difficulty in creating conditions favorable for vegetation growth. Thus, numerous remediation technologies have focused on increasing soil nutrient composition, as well as the number and activity of plant growth-promoting bacteria (PGPB), given that they stimulate host plant growth by increasing the availability of essential nutrients (phosphorus, nitrogen, manganese, iron), producing phytohormones, and providing protection from pathogens. The main objective of this research was to characterize autochthonous plant and microbial overburden communities and access their ability to restore these contaminated soils. Phytocenological analysis of vegetation and plant species was performed according to Flora Europaea (2001), from 2011 - 2013. Our results show that plant species were not detected at mine overburden soil in 2011. However, we detected presence of a single plant species, Amaranthus albus L., in 2012. Further, we recorded the presence of five families (Amaranthaceae, Chenopodiaceae, Convolvulaceae, Poaceae and Polygonaceae) in 2013. Microbial abundance and enzymatic activity were also examined during the same period. The diversity of microbial populations in the first year was rather small. Two Bacillus spp., B. simplex and a B. cereus group member, indigenous to mine overburden were isolated and identified using standard macroscopic and microscopic, as well as molecular techniques (Hamidovic et al., submitted). Phosphate solubilizing activity of bacteria was tested on National Botanical Research Institute's phosphate growth medium (1999). Production of ammonia was determined in peptone water with Nessler

  4. Technology of preventing drilling hole collapse in soft coal seam by inserting casing in drill pipe%钻杆内下套管防治软煤层钻孔塌孔技术

    Institute of Scientific and Technical Information of China (English)

    李定启; 邓广涛; 李海贵; 王明中

    2015-01-01

    In order to prevent collapse and block of drilling hole in short time when conducting gas extraction in soft coal seam, and improve the gas drainage efficiency of drilling, the equipments and methods of inserting casing in drill pipe for soft coal seam were analyzed and studied.By comparing and analyzing the experimental results in soft coal seam with conventional technology of casing running, original technology of inserting casing in drill pipe and improved technology of inserting casing in drill pipe, it showed that:the length of inserting casing by the improved technology is much greater than that by conventional technology, and the design of drill bit and drilling rob on e-quipment of inserting casing in drill pipe have a greater influence on the drilling and length of inserting casing.In the design, the diameter of drilling bit should be moderate and the smooth joint connection should be adopted on drilling rob.The gas drainage capacity of drilling per hundred meters by this technology is much greater than that by ordinary technology.%为了防止软煤层钻孔在瓦斯抽采过程中短时间内塌孔堵死,提高钻孔瓦斯抽放效率,对软煤层钻孔钻杆内下套管设备和工艺方法进行了分析和研究。通过对比分析常规下套管方式、原有钻杆内下套管方式和改进后钻杆内下套管方式的在软煤层试验,得出以下结论:采用钻杆内下套管设备下套管的长度远大于采用常规钻进方式下套管的长度;钻杆内下套管设备的钻头和钻杆设计对钻进和下套管长度影响较大,设计时钻头直径大小应适中,钻杆应尽量采取内平丝扣连接;采用钻杆内下套管方式的百米钻孔瓦斯抽放量要远大于普通钻进下套管钻孔的百米钻孔瓦斯抽放量。

  5. Impact of Calcium on Pyrolysis and Gasification Characteristics of Brown Coal%钙元素对褐煤热解和气化特性的影响

    Institute of Scientific and Technical Information of China (English)

    王磊; 余江龙; 尹丰魁; 王冬梅

    2012-01-01

    综述了钙元素对褐煤热解和气化特性的影响,讨论了钙元素对热解产物中挥发分、焦油产率和气体产物分布的影响,以及对褐煤半焦气化的催化作用.结果表明,与酸洗煤相比,热解过程中,钙元素降低焦油产率,提高半焦产率;气化过程中,钙元素的植入提高褐煤半焦的反应活性,缩短了反应时间.高温时钙元素主要以氧化态的形式存在,低温时则不断与半焦基体键合而参与交联反应,少部分挥发.%This paper provides an overview on the impact of calcium on the pyrolysis and gasification characteristics of brown coal. The impact of calcium on the total volatile matter yield, the tar yield and the distribution of gaseous products during pyrolysis as well as its influences on the catalysis of the gasification of brown coal and chars are discussed. It is shown that the tar yield of the Ca-enriched coal is lower than that of the acid-washed coal and the char yield is higher than that of the acid-washed coal in the pyrolysis process. The reactivity of brown coal is increased and the reaction time is shortened in the gasification process because of the calcium implantation into the brown coal. Calcium oxide is the main form existing in the coal at high temperatures, but it is strongly bonded to the char structure and attends cross linking reactions and a small proportion of volatilizes.

  6. 三软厚煤层综采工作面采动应力分布规律研究%Study on Mining Stress Distribution Law of Fully Mechanized Coal Mining Face in Thick Seam with Soft Roof,Soft Coal and Soft Floor

    Institute of Scientific and Technical Information of China (English)

    吕梦蛟; 李先章; 李玉申

    2011-01-01

    The mining stress would cause the roof and floor broken and failure,spalling and roof falling,floor heave of the seam and would cause the mine pressure bumping and the coal and gas outburst occurred.The site stress measurement and the numerical simulation combined method was applied to study the mining stress distribution law of the fully mechanized coal mining face in the seam with soft roof,soft coal and soft floor in Jiaojiazhai Coal Mine.The results showed that the pilot support pressure and stress reducing area was at a distance of 0—12 m in front of the coal mining face,the stress increased area was at a distance of 12—40 m in front of the coal mining face,the stress stable area was beyond 40 m in front of the coal mining face and the stress concentration coefficient was 1.4-1.7.There was a stress reduced area formed within a scope of 0—14 m of the lateral support pressure area,a stress increased area formed in the scope of 14—36 m and the stress sable area formed beyond 36 m.the analysis showed that the deformation and failure of the air return gateway in No.51109 coal mining face in Jiaojiazhai Mine was located under the lateral support pressure increased area formed by the above seam mining face.%由于采动应力会导致煤层顶板垮断冒顶、巷道底鼓以及冲击矿压和煤与瓦斯突出发生,因此采用现场应力测试和数值模拟相结合的方法,研究了焦家寨煤矿三软厚煤层综采面采动应力分布规律,结果表明:距离工作面0—12 m为超前支承压力降低区、12—40 m为增高区、40 m以外为稳定区,应力集中系数为1.4-1.7;侧向支承压力在0—14 m形成应力降低区,在14—36 m形成应力增高区,36 m以外进入应力稳定区。

  7. 新疆阜康矿区煤层孔隙结构特征的氮吸附实验研究%Nitrogen adsorption experimental study on pore structure characteristics of coal seams in Xinjiang Fukang mining area

    Institute of Scientific and Technical Information of China (English)

    林海飞; 程博; 李树刚; 曾强; 张雪涛; 成连华

    2015-01-01

    为研究新疆阜康矿区主采煤层吸附孔孔隙结构特征,选取该矿区四个典型煤样,基于低温氮吸附实验绘制了煤样的吸附解吸等温线,得到煤的孔隙直径,采用BET模型和BJH模型计算了孔隙比表面积和体积等参数,分析了煤样孔隙比表面积及体积分布规律.结果表明:新疆阜康矿区煤的吸附解吸等温线回滞环很小,吸附孔以一段开口的均匀圆筒形孔为主.煤样吸附孔发育程度差别明显,导致各煤层对瓦斯吸附储存能力有所不同.各煤样孔径分布较为均衡,比表面积以过渡孔占比最大,其次为微孔及中孔;过渡孔和中孔的孔隙体积占比较大,微孔较小.煤样孔隙体积分布规律基本一致,比表面积在过渡孔和中孔范围内分布规律相同,微孔范围内分布差异较大.%To study the adsorption pore structure characteristics of main coal seam in Xinjiang Fukang mining area,four typical coal samples were selected in this mining area. Based on the experimental re-sults of low temperature nitrogen adsorption,the adsorption and desorption isotherms of coal samples were drawn,and the pore diameter is obtained. Using the BET theory and BJH theory,pore specific surface area and volume of coal samples are calculated. The distributions of pore specific surface and volume of coal samples were analyzed. The experimental results show that the adsorption and desorption isotherms of coal in Fukang mining area have very small hysteresis loop ,and most of the pores are cylin-drical with one end open. The difference of adsorption pore development degree of coal sample is obvi-ous,which causes different storage capacity of gas adsorption of coal seam. The average pore sizes of each coal sample are approximately the same. The specific surface area of transition pores accounted for the largest surface area of adsorption pore ,followed by micropore and mesopore;the volume of transition pore and mesopore accounted for the largest

  8. 含水松散层下厚煤层采掘溃砂危险性分析%Sand Inrush Hazard Analysis of Thick Coal Seam Mining Under Water-bearing Unconsolidated Strata

    Institute of Scientific and Technical Information of China (English)

    符辉; 蔡先锋; 冯锐敏; 于辉

    2012-01-01

    For the projects difficulties of sand inrush of thick coal seam mining under water-bearing unconsolidated strata,the paper carries out scientific analysis of hydro-geological conditions,including the lithology,thickness,and water yield property of water-bearing unconsolidated strata,reasonable size of leaving safety coal and rock pillars in thick seam slicing mining is discussed and the corresponding mining methods are decided.On the basis,the heights of caving zone and water conducted zone were predicted,mining method was decided.Based on the powerful data processing capabilities of GIS,the risk of sand inrush caused by multiple factors are analyzed quantitatively,and sand inrush risk zoning map was also drew eventually.%针对含水松散层下厚煤层采掘溃砂工程难点,对含水松散层的岩性、厚度和富水性等水文地质条件进行研究,探讨了厚煤层分层开采留设安全煤岩柱合理尺寸,并确定了相应的开采方法;预计了(垮落带和导水裂隙带)"两带"高度,基于GIS的强大数据处理功能,对多因素引起的采动溃砂危险性进行了量化评价,分析得出了分层开采条件下顶板溃砂危险性分区图。

  9. Influence of coal mining on the deformation-failure and permeability of seam floor%煤炭开采对煤层底板变形破坏及渗透性的影响

    Institute of Scientific and Technical Information of China (English)

    孟召平; 王保玉; 徐良伟; 吴志远; 白刚; 路波涛

    2012-01-01

    Except the geological factors, the deformation and failure of seam floor are also controlled by mining factors. The influence of coal mining on stress-strain and permeability of seam floor in working face and its failure regularities were studied through theoretical analysis and the experiment. The research result shows that the permeability of the rock with different lithology is a function of strain in the process of complete stress-strain. In the micro-fracture closure and elastic deformation stage, the primary pores and cracks of rocks are easily compacted, it is obviously that rock permeability decreases with the increase of stress, when the stress intensity increases to the limit, the rock sample is destroyed and cracks through the sample are formed,, the rock permeability rapidly increases to the maximum. There are some differences between rocks with different lithology. With advancement of working face, the seam floor rocks are divided into four areas horizontally, they are initial stress area, advanced stress compression area, direct damaged area of mining stress and stress recovery area of floor rock mass. Permeability of seam floor rock shows regular variation with the deformation and failure of seam floor rock during coal mining.%煤层底板变形破坏除受地质因素控制外,还受开采因素影响.通过试验和理论分析,系统研究了煤炭开采对回采工作面底板应力、应变和破坏及渗透性的影响.研究结果表明,不同岩性岩石的渗透性在全应力-应变过程中为应变的函数,在微裂隙闭合和弹性变形阶段,岩石的原生孔隙和裂隙容易被压密,岩石的渗透率随应力的增加由大变小明显,当应力增大至极限强度时岩石试件破坏形成贯穿裂隙,岩石的渗透率迅速增大至最大,不同岩性岩石存在一定差异性;随着回采工作面推进,煤层底板岩层在横向上划分为原岩应力区、超前压力压缩区、采动矿压直接破坏区和

  10. Comparative study of cogasification and co-combustion of communal sewage sludge in brown coal fuelled plants; Vergleich der Mitvergasung und Mitverbrennung kommunaler Klaerschlaemme in braunkohlegefeuerten Anlagen

    Energy Technology Data Exchange (ETDEWEB)

    Schiffer, H.P.; Bierbaum, K.; Adlhoch, W.; Thomas, G. [Rheinbraun AG, Koeln (Germany)

    1996-12-31

    Co-combustion and cogasification of sewage sludge in brown coal fuelled plants are compared, and an economic assessment is made. (ABI) [Deutsch] Die Mitverbrennung und Mitvergasung von Klaerschlamm in braunkohlegefeuerten Anlagen werden verglichen und auf ihre Wirtschaftlichkeit hin untersucht. (ABI)

  11. Analysis of Ground Behavior Regularity of Fully Mechanized Face with Extra Thick Coal Seam%特厚煤层综放工作面矿压显现规律分析

    Institute of Scientific and Technical Information of China (English)

    任永康; 李宝富; 王富林

    2011-01-01

    The paper used methods of field strata control observation and RFPA numerical simulation to analyze and study ground behavior regularity of fully mechanized face with extra thick coal seam of easy spontaneous combustion in Gengcun Coal Mine. The results showed that there is acute ground behavior in 12170 fully mechanized face of Gengcun Coal Mine and obvious phenomenon of periodic loading in main roof whose average interval was 16.06 m; in whole range of fully mechanized face, phenomenon of periodic loading in main roof has obvious variance, namely loading strength is large in middle-lower and lower areas while small in upper and middle-upper areas; hydraulic supports have enough supporting resistance and high reliability in stoping process, which can satisfy requirements of fully mechanized caving of 2-3 extra thick coal seam; the result of RFPA numerical simulation is consistent with the one of field strata control observation, which showed validity of the method of RFPA numerical simulation about analyzing strata behavior regularity.%采用现场矿压观测和RFPA数值模拟方法对耿村煤矿易自燃特厚煤层综放工作面矿压显现规律进行了分析研究.结果表明,耿村煤矿12170综放工作面存在比较剧烈的矿压显现,老项存在较明显的周期来压现象,老顶周期来压平均步距为16.06 m;整个工作面全长范围内,老顶来压具有明显的不一致性,即中下部和下部来压强度大,上部和中上部来压强度小;综放支架在回采过程中支护阻力充足,其可靠性较好,能够适应2-3特厚煤层综放开采的要求;RFPA数值模拟结果与现场矿压观测结果一致,表明了RFPA数值模拟方法应用于矿压显现规律分析的有效性.

  12. Mineral composition of rock in Visonia lignite and Nograd brown coal and its influence on abradability

    Energy Technology Data Exchange (ETDEWEB)

    Szalay, Z.

    1984-01-01

    A study is made of the properties of coals when they are reprocessed in a crusher and tubular furnace at the Gagarin heat and electric power plant and the characteristics of the forming fly ash. The coals are distinguished by high percentages (15-28%) of montmorillonite and kaolinite (3-13%). DTA and x-ray structural analysis of the coals and solid residues were conducted. It is shown that the fly ash is mainly formed from clay minerals and consists of an amorphous mass and modifications of free SiO/sub 2/.

  13. Experimental research on low permeability coal seams group of first layer hollow out coal mining without pillars for release of eliminate the highlight and gas control%低透气性突出煤层群首采层掏心无煤柱开采卸压消突与瓦斯治理试验研究

    Institute of Scientific and Technical Information of China (English)

    姚尚文; 卢平; 张纯如; 李庆明

    2015-01-01

    针对深井高瓦斯低透气性突出煤层群消突和首采层开采卸压瓦斯治理难题,以谢桥煤矿11426工作面开采为例,设计首采中间层无煤柱开采、实现上下突出煤层均消突的技术方案,研究了Y型通风工作面采空区瓦斯及风压分布规律,结合煤层群开采巷道布置条件,提出并实施留巷侧井下暗立眼回风阶段留巷Y型通风技术,强化留巷墙体封闭和留巷采空侧回风立眼封闭等卸压瓦斯抽采技术,实现了深井煤层群首采层工作面的安全高效回采和邻近突出煤层的全面消突。11426工作面回采期间,绝对瓦斯涌出量最大47.67 m3/min,工作面瓦斯抽采率高达65%以上,研究成果为今后类似深井煤层群开采的卸压瓦斯抽采和治理提供技术指导。%As for the problem of deep gas low permeability outburst coal seam group of release of eliminate the highlight and pressure relief and the gas control of first layer mining, based on Xeqiao mine 11426 working face mining as an example,the design of first layer without coal pillar mining,realize technical proposal on up and down coal seams of eliminate the highlight,research laws of goaf gas and wind pressure distribution on Y type ventilation working face,combinate condition on multi-seam mining of roadway layout,innovation present and implementation technology of the side for downhole dark set eyes return air phase for Y type ventilation,strengthen technology of the walls closed and the goaf side return for eye closed on pressure relief gas extraction, realized the working face of deep coal seam group of first floor safe and efficient mining and adjacent coal seams outburst elimination. During the 11426 mining face,the absolute gas emission maximum 47.67 m3/min,the working face gas extraction rate as high as 65%above,provide technical guidance on research of pressure relief gas extraction and government from similar deep well multi-seam mining for the

  14. Thick Coal Seam Repetition Mining under Open Waters with Thin Basement in Shallow%浅埋深薄基岩地表水体下厚煤层重复开采研究

    Institute of Scientific and Technical Information of China (English)

    李磊

    2016-01-01

    The possibility of working face water flowing fractured zone with thin basement in shallow could connected aquifer and sur-face water was large, then the working face would faced water inrush risk, on the basis geological and mining situation of one coal mine in Erdos district, the broken height of overburden that caused by mining was predicted, and then the water proof coal pillar was layout for surface water, the thick coal seam repetition mining scheme under the surface water was put forward, then mining working face safety realized, it references for coal resource mining with similar situation of Erdos district.%浅埋深薄基岩工作面导水裂缝带存在导通含水层及地表水的可能性,最终造成工作面突水的威胁。基于鄂尔多斯某矿实际地质采矿条件进行分析,对煤层开采的覆岩破坏高度进行预计,针对地表水体留设了防水煤岩柱,最终得出了地表水体下厚煤层重复开采的方案,并实现了工作面的安全开采,为鄂尔多斯地区解决类似条件下煤炭资源的回采提供了参考。

  15. Reduction of sulfur content of brown coals and lignites by hydrothermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, P.; Wolf, G.; Bognar, T.

    1987-01-01

    The hydrothermal experiments were carried out in acid-proof autoclaves. The experimental conditions are described and the results are summarized for different coal types. The heat treatment reduces the organic sulfur content and increases the calorific value. From 300 degrees C the pyritic sulfur can be separated from the other forms of sulfur. By the hydrothermal treatment the bitumen content to be extracted by benzene-alcohol mixture also increased in thermo-coals.

  16. SPECIFIC HEAT CAPACITY AND THERMAL CONDUCTIVITY OF HEAT STORAGE MATERIALS BASED ON PARAFFIN, BROWN-COAL WAX AND POLYETHYLENE WAX

    Directory of Open Access Journals (Sweden)

    Snezhkin Yu.

    2014-08-01

    Full Text Available The present paper overviews heat storage materials (HSM with phase change based on organic compounds. They consist of paraffin, brown-coal wax and polyethylene wax. These materials are produced on an industrial scale for the foundry work. It is shown that heat capacity of HSM in the solid and liquid states can be used for heat storage in addition to the heat of phase change. The results of investigations of phase change during heating and cooling HSM are presented. The studies are carried out by differential scanning calorimetry (DSC. The measurement techniques of the specific heat capacity and the coefficient of thermal conductivity are shown. Temperature dependences of the specific heat capacity of HSM in the solid and liquid states are researched by DSC. Values of the coefficient of thermal conductivity are determined by contact stationary technique of the flat plate over the entire temperature range of the operation of heat storage system.

  17. Impermeability and Mining Impacts of Key Aquifuges for Shallowly Buried Coal Seams%浅埋煤层关键隔水层隔水性能及采动影响变化

    Institute of Scientific and Technical Information of China (English)

    蒋泽泉; 王建文; 王宏科

    2011-01-01

    The mining of shallowly buried coal seams has brought a series of ecological environmental problems; water conservation coal mining is the key issue in coal resource scientific mining in the northern Shaanxi and even whole Northwest China. Taking the Shennan mining area as an example, the paper studied impermeabilities of loess and red loam aquifuges and mining impacts on them.Coal seams in water conservation mining are covered with clay and sands; the overlying clay is the crucial aquifuge. Laboratory and field tests have demonstrated that: after the overlying clay is disturbed, water inflow will soar to rise rapidly and form fissure flow, that is went against to water conservation coal mining. When loess is subjected to the ground surface tension fissure developed shearing will be in broken state, permeability coefficient variation will appear as some orders of magnitude after mining; while the red loam is stand in the integral settlement zone, subjected to additional stress and is indicative of greater plastic deformation, permeability is reduced after mining, thus in favor of water conservation coal mining. To realize water conservation coal mining and keep clay bed undisturbed integrally, gob area stowing is advised to control surface subsidence and soil mass confining pressure. When surface subsidence is reduced, loess bed can keep undisturbed, and confining stress is existed, clay bed stability can also be kept.%陕北浅埋煤层开采引起了一系列的生态环境问题,保水采煤成为陕北乃至整个西北地区煤炭资源科学开采的关键.以神南矿区为例,研究了黄土、红土隔水层的隔水性及采煤对其隔水性的影响.神南矿区砂土基型煤层的保水开采的关键隔水层为上覆粘土层,室内、外试验显示:粘土层失稳后流量猛增形成裂隙流,不利于保水采煤;黄土受地面张裂隙发育的剪切作用处于破碎状态,采动后渗透系数表现为数个数量级的变化;红土处于

  18. 近水平中厚煤层水患形成机理及防治%NearlyLevel in Thick Coal Seam Formation Mechanismand the Flood Prevention and Control

    Institute of Scientific and Technical Information of China (English)

    熊天君

    2015-01-01

    Through codium coal company through a mine E2807 happened twice in the process of min-ing face floods caused great economic losses of instances ,and combining the codium mining area through one ore more than 40 years nearly horizontal floods in thick coal seam mining and the preven-tion and control experience ,from the formation mechanism of flood and flood prevention and control technology ,analyzes the problems existing in the prevention and control of water management for the colleague reference.%通过松藻煤电公司打通一矿E2807工作面回采过程中两次发生水患造成重大经济损失的实例,并结合松藻矿区打通一矿40多年近水平中厚煤层回采中发生的水患及防治经验,从水患形成机理,水患防治技术,防治水管理存在的问题进行剖析,供同行参考。

  19. 浅部厚煤层开采上限确定关键技术研究%Research on key technology of determining upper mining limit of shallow thick coal seam

    Institute of Scientific and Technical Information of China (English)

    陈军涛; 孙洪华; 蔡辉

    2011-01-01

    High density resistivity tomography imaging technique was used to detect fluctuant change of Quaternary bottom interface in the northern 4th mining area based on the geologic survey of Shenjian coal mine in Caiyuan. "Two Zone" was determined applying calculation numerical analysis, and the upper mining limit of 3 coal seam was finally determined by using television imager to measure the height of caving zone and water flowing fractured zone of adjacent 4 layers in mining area.%在蔡园生建煤矿地质勘测的基础上,采用高密度电阻率层析成像技术探测四采区北部第四系底界面的起伏变化,运用计算数值分析确定"两带"高度,采用电视成像仪实测相邻四个分层已全部开采区域的垮落带及导水裂隙带高度,最终确定3煤层开采上限.

  20. 深部厚煤层断层三维地质建模应用研究%Deep thick coal seam faults of 3D geological modeling application research

    Institute of Scientific and Technical Information of China (English)

    张运国; 赵万庆; 司雨

    2014-01-01

    位于滕南煤田的田陈煤矿多元化地质构造发育,为更准确地反映地质构造要素之间的空间关系,论文对田陈煤矿三维地质建模及可视化应用进行了研究。基于solidworks对工作面巷道、煤层、断层进行建模,对工作面构造形态分析,安全生产及提高资源回收有很大指导意义。%Tian Chen Coal Mine diversified geological structure in Tengnan coalfielddevelopment, spatial relations more accurately reflect the geological structureelements, the thesis carries out research on Tian Chen mine 3D geological modeling and visualization applications. SolidWorks on the working face, coal seam roadway, fault in modeling based on analysis of the structure, the working face, the safety production and has great guiding significance to improve resource recovery.

  1. 单一煤层开采过程中损伤场的分布及演化规律%Distribution and Evolution Law of the Damage Field in Single Coal Seam Mining Process

    Institute of Scientific and Technical Information of China (English)

    许爱斌; 高峰; 程红梅; 刘星光

    2012-01-01

    为实现单一煤层采煤工作面瓦斯安全高效抽采、减小煤与瓦斯突出危险,特从损伤力学的角度入手,研究其损伤场的分布及演化规律。引入与开采步序相关的损伤变量,通过损伤度来描述岩体裂隙的分布特征,并根据弹塑性损伤理论编写了三维有限元程序,利用此程序对一工作面开采过程进行分析,给出了考虑材料损伤累积条件下围岩损伤场、体积应变和应力场的分布及演化规律。计算结果可为指导单一煤层卸压瓦斯抽放设计、提高瓦斯抽采率等提供理论依据。%In order to realize the safe and high-efficient exploitation of gas and reduce the risk of coal and gas outburst in single coal seam,the distribution and evolution law of the damage field was studied by means of damage mechanics.The damage variable correlated with the excavation process was introduced,which was used to describe the distribution characteristics of fractures in rock mass.According to the elastoplastic damage theory,the 3D-finite element program was developed,by which the analysis of mining process of one coal seam was made.The material damage accumulation taken into consideration,the distribution and evolution law of the damage field,volume strain and stress was obtained,which can provide a theoretic reference for the design of gas drainage and improving the efficiency of gas extraction.

  2. 工作面顶底板泥化机理分析与防治技术研究%Study on Mechanism and Prevention for Argillization in Roof and Floor of Thin Coal Seam

    Institute of Scientific and Technical Information of China (English)

    李林; 李付臣; 李华

    2014-01-01

    In order to grasp the muddy mechanism of roof and floor in thin coal seam, guarantee the safe production of tunneling and mining face, the subject determines massive hydrophilic substances such as montmorillonite and illite in mudstone by experiment analysis of mineral composition and relative quantitation. The combination of hydrophilic substances and water source from workingface makes mudstone in the floor of coal seam disintegrate and leads to environmental deterioration of workingface, serious influence on producting equipment. According to on-site survey of No.6212 workingface in Baodian Coal Mine durimg tunneling period, the subject takes comprehensive measures to control argillization of floor, especially heavily muddy area. The main measures are mandatory exclusion with submersible pump and slurry pump, de-watering roadway hydrocephalus, laying roadbed with artificial fabric and reasonable optimization of spray parameters. It effectively prevents the argillization of floor, improves the environment of workingface, reduces the labor intensity, raises operation rate of mining machine and en-sures the normal production of the face.%根据对鲍店煤矿6212工作面巷道掘进期间的现场调研,通过底板泥岩的矿物组成和相对定量分析实验,确定泥岩中有大量的蒙脱石和伊利石等亲水性物质,与工作面的水源结合,使得底板泥岩泥化崩解,造成了工作环境的恶化,对设备和生产造成严重影响。对泥化严重区域,以综合技术措施防治底板泥化。利用潜水泵和泥浆泵强排、疏干巷道积水,选择人工织物铺设路基,利用加筋作用改变泥岩受力状态,有效防止了掘进期间的底板泥化;利用工作面喷雾降尘用水量参数的合理优化,使得采煤工作面的环境大有改观,从一定程度上减小了工作面工人的劳动强度,提高了采煤机开机率,保证了工作面的正常生产。

  3. Parameters and Characteristics of Self-Priming Abrasive Jet Nozzle for Cutting Coal Seam%煤层水力割缝自吸磨料喷嘴特性与参数

    Institute of Scientific and Technical Information of China (English)

    张欣玮; 卢义玉; 汤积仁; 周哲

    2015-01-01

    High-pressure water jet becomes invalid in cutting hard coal seam,and abrasive jet cutting technology is difficult to achieve continuous addition of abrasives.In order to overcome these difficulties,a self-priming abrasive jet nozzle using the forward and backward nozzle structure was designed on the basis of the principle of ejector.This nozzle can achieve continuous inhalation of coal particles produced by slotting to form abrasive jet,with the slotted capacity improved.By simulating the two-phase liquid-solid interaction,it was found that coal particles in the nozzle experience three acceleration stages at intake, mixing chamber and nozzle, respectively.According to the volume of particles and the final velocity of the particles,the most optimal nozzle structure was obtained:the front nozzle diameter is 3 mm,the back nozzle diameter is 5 mm,and the length of the back nozzle is 15 mm.The comparison of the experiments results showed that the slotting efficiency of the self-priming abrasive nozzle was improved significantly compared to that of the traditional cutting seam.%针对煤矿纯水射流割缝遇硬煤失效,而磨料射流割缝技术难以实现磨料连续添加等问题,基于引射原理,采用前后双喷嘴结构,设计出一种自吸式磨料射流割缝喷嘴,可以连续吸入割缝产生的煤粒形成磨料射流,提高割缝能力.通过液固两相数值模拟,发现煤粒在喷嘴内经历了3个加速阶段:吸入口加速段、混合腔加速段和后喷嘴加速段.以提高吸入量和最终煤粒的速度为指标,得到喷嘴的最优结构:前喷嘴直径为3 mm,后喷嘴直径为5 mm,后喷嘴长度15 mm.对比割缝实验结果表明,自吸式磨料射流割缝喷嘴的割缝效率较传统割缝喷嘴明显提高.

  4. 低透气性煤层CO2增透预裂技术应用%Application of CO2 Anti-reflection Pre-split Technology in Low Permeability Coal Seam

    Institute of Scientific and Technical Information of China (English)

    张悦; 张民波; 朱天玲; 冯世梁; 雷博龙

    2013-01-01

    针对低透气性煤层掘进过程中,瓦斯抽放难度高、掘进效率低等难点问题,提出应用CO2增透预裂技术,提升煤层透气性系数与瓦斯抽放效率,提高工作面掘进效率.应用岩土力学模拟软件,模拟分析了煤层掘进过程中煤体破坏分布与应力分布状态.模拟结果表明:掘进过程中,巷道两帮破碎区域为距巷帮0~3m的范围,巷帮主要应力集中区域为距巷帮3~4m的区域,应力为18.0~18.9MPa.根据数值模拟结果,设计了煤层CO2增透的预裂孔与抽放孔的详细参数,进行了现场验证.现场试验与效果分析表明:预裂前后钻场瓦斯抽采瓦斯纯流量提高了27%,瓦斯抽放浓度提高了1.7倍,可解吸瓦斯量由7.27降到4.30m3/t,掘进效率明显提高.%Aiming at the highly difficult gas drainage and low efficient drivaging of low permeability coal seam drivaging process of a coal mine,CO2 anti-reflection pre-splitting technology was put forward to improve seam permeability coefficient,gas drainage efficiency and working face drivaging efficiency.Rock mechanics simulation software was applied to simulate and analyze the coal damage distribution and stress distribution state in coal seam drivaging process.The simulation results showed that,the broken area on both sides of the roadway is 0-3m from one side,and the main stress concentrated area of roadway sides is 3-4m from roadway sides,the stress intensity ranges from 18.0 to 18.9MPa in the drivaging process.Meanwhile,according to the simulated conclusions,detail parameters of pre-splitting and drainage drill holes were designed specifically.Field tests and effect analysis showed that,the net flow of gas drainage is increased by 27%,drainage concentration by 1.7 times,and desorption gas quantity is reduced from 7.27 to 4.30 m3/t in each dill site after pre-splitting,significantly improving the drivaging efficiency.

  5. Thermogravimetric study of the combustion of Tetraselmis suecica microalgae and its blend with a Victorian brown coal in O2/N2 and O2/CO2 atmospheres.

    Science.gov (United States)

    Tahmasebi, Arash; Kassim, Mohd Asyraf; Yu, Jianglong; Bhattacharya, Sankar

    2013-12-01

    The combustion characteristics of microalgae, brown coal and their blends under O2/N2 and O2/CO2 atmospheres were studied using thermogravimetry. In microalgae combustion, two peaks at 265 and 485°C were attributable to combustion of protein and carbohydrate with lipid, respectively. The DTG profile of coal showed one peak with maximum mass loss rate at 360°C. Replacement of N2 by CO2 delayed the combustion of coal and microalgae. The increase in O2 concentration did not show any effect on combustion of protein at the first stage of microalgae combustion. However, between 400 and 600°C, with the increase of O2 partial pressure the mass loss rate of microalgae increased and TG and DTG curves of brown coal combustion shifted to lower temperature zone. The lowest and highest activation energy values were obtained for coal and microalgae, respectively. With increased microalgae/coal ratio in the blends, the activation energy increased due to synergy effect.

  6. Experimental Studying of the Shortest Natural Spontaneous Combustion Period of 3-1 Coal Seam of Menkeqing Coal Mine%门克庆煤矿3-1煤层最短自然发火期实验研究

    Institute of Scientific and Technical Information of China (English)

    孙喜贵; 徐长富; 姚海飞; 张群; 吴海军

    2016-01-01

    最短自然发火期是衡量煤自然发火危险性的重要指标之一。为了科学地测试煤层最短自然发火期,以门克庆3-1煤层为研究对象,利用煤的绝热氧化反应装置,测试了煤样升温过程中各种气体的生成量,确定了3-1煤的交叉点温度,并根据生成的CO与CO2键能值计算氧化升温过程中的放热量,再根据差示扫描量热实验测定了不同温度时煤的比热容,进而分段计算达到交叉点温度所需要的时间。结果表明:门克庆煤矿3-1煤自燃倾向性等级属于I类,最短自然发火期43d,为煤矿制定有效防灭火措施提供了依据。%The shortest natural spontaneous combustion was an important indicator of natural spontaneous combustion risk evalua-tion. In order to test the shortest natural spontaneous combustion scientific, it taking 3-1 coal seam of Menkeqing coal seam as studying object, and isolated heat oxidation reaction device was utilized, the production of all kinds gases were test during temperature rise pe-riod, and the intersection temperature of 3-1 coal seam was confirmed, and the heat release during oxidation temperature rise period was calculated by chemical bond energy value of CO and CO2 that generated, and the specific heat capacity of coal in different temper-ature was test on the basis of DSC, and then the lasting time that reached intersection point temperature was calculated partition. The results showed that the natural spontaneous combustion tendency was belong I classification, the shortest natural spontaneous combus-tion period was 43d, it references for valid fire precaution formulated of coal mine.

  7. Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal. Part IV. Catalytic effects of NaCl and ion-exchangeable Na in coal on char reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Dimple Mody Quyn; Hongwei Wu; Jun-ichiro Hayashi; Chun-Zhu Li, [Monash University, Monash, Vic. (Australia). CRC for Clean Power from Lignite, Department of Chemical Engineering

    2003-03-01

    The purpose of this study is to investigate the catalytic effects of Na as NaCl or as sodium carboxylates ( COONa) in Victorian brown coal on the char reactivity. A Na-exchanged coal and a set of NaCl-loaded coal samples prepared from a Loy Yang brown coal were pyrolysed in a fluidised-bed/fixed-bed reactor and in a thermogravimetric analyser (TGA). The reactivities of the chars were measured in air at 400{sup o}C using the TGA. The experimental data indicate that the Na in coal as NaCl and as sodium carboxylates ( COONa) had very different catalytic effects on the char reactivity. It is the chemical form and dispersion of Na in char, not in coal, that govern the catalytic effects of Na. For the Na-form (Na-exchanged) coal, the char reactivity increased with increasing pyrolysis temperature from 500 to 700{sup o}C and then decreased with pyrolysis temperature from 700 to 900{sup o}C. The increase in reactivity with pyrolysis temperature (500 700{sup o}C) is mainly due to the changes in the relative distribution of Na in the char matrix and on the pore surface. For the NaCl-loaded coals, when Cl was released during pyrolysis or gasification, the Na originally present in coal as NaCl showed good catalytic effects for the char gasification. Otherwise, Cl would combine with Na in the char to form NaCl during gasification, preventing Na from becoming an active catalyst. Controlling the pyrolysis conditions to favour the release of Cl can be a promising way to transform NaCl in coal into an active catalyst for char gasification. 38 refs., 5 figs.

  8. 采空区积水下急倾斜厚煤层水平分层综放开采安全性分析%Safety Analysis of Steeply Inclined Thick Coal Seam with Fully Mechanized Top Coal Caving Mining under Goaf Water

    Institute of Scientific and Technical Information of China (English)

    贾立明; 张玉军

    2015-01-01

    Quaternary gravel aquifer and the goaf water are the main threat of safety mining of steeply inclined thick coal seam with fully mechanized top coal caving mining in Meihe mining area. It is an important problem to be solved. Taking Mitsui 5109 zone as the research area,based on the transient electromagnetic sounding and the goaf water of and the failure height pre-diction on horizontal overburden of the steeply inclined thick coal seam,abundant coal pillars for the water barrier at F4 fault are set. In the light of the strata movement law,it is calculated that the mining influence in working face spread to the goaf water are-a. The evaluation shows that:before mining,the elevation of goaf water just declined to +172 m can ensure the safety mining.%第四系沙砾含水层及采空区积水是梅河矿区急倾斜特厚煤层残采区综放安全复采的主要威胁,也是亟待解决的重要问题。以三井5109区为研究区域,在对采空区积水瞬变电磁探测和对急倾斜特厚煤层水平分层覆岩破坏高度预计的基础上,对F4断层留设了足够的隔水煤柱,并针对岩层移动规律,求算出工作面采动影响波及到的采空区积水区的范围,评价结果认为:在回采前要确保采空区积水降至+172 m标高以下方能保证安全开采。

  9. 浅埋煤层穿越河道采煤的实践与研究%Practices and Study on Coal Mining in Shallow Depth Seam Passing Through River Bed

    Institute of Scientific and Technical Information of China (English)

    王建文; 王宏科; 陈菲

    2012-01-01

    为防止煤层回采过程中地表水通过导水裂缝带流入井内,威胁矿井安全,基于神府矿区柠条塔煤矿N1201工作面新民沟区域富水区水文地质条件,运用经验公式计算出该工作面回采后,工作面上方地表河流段会形成塌陷区,塌陷后的导水裂缝带高约60 m,使工作面与地表相贯通,通过SF6气体试验得以证实。为此采用在井下设置排水仓、地表安设排水管道、河道裂缝处开挖充填等综合技术防止地表水向井下下渗,结果表明,回采过程中工作面涌水量仅较原来增加了4.7m3/h,实现了穿越河道浅埋煤层安全开采。%In order to prevent the surface water rushed into the mine through the water flow fissure zone during the seam mining operation to threaten the mine safety,based on the hydrological investigation conducted on the watery zone of Xinmingou Area for No.1201 coal mining face in Ningtiaota Mine of Shenfu Mining Area,the calculation with the experience formula showed that after the mining of the coal mining face,the river section of the surface ground above the coal mining face would be formed as a subsidence area.After the subsidence occurred,the height of the water flow cracking zone would be about 60 m and the water flow from the surface ground to the coal mining face would be connected.The SF6 gas experiment showed that the water drainage sump set in the underground mine,the water drainage pipeline set on the surface ground,the excavation and backfill of the river course and other comprehensive technology could be applied to prevent the surface ground water running into the underground mine.The results showed that during the mining process,the water inrush value in the coal mining face was 4.7 m3/h higher than the previous coal mining face.Thus a safety mining in the shallow depth seam was conducted passing through the river bed.

  10. Effects of lithium iodide doping on devolatilization characteristics of brown coals; Yoka lithium no tenka ga kattan no kanetsu henka katei ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Muraoka, J.; Kumagai, H.; Hayashi, J.; Chiba, T. [Hokkaido University, Sapporo (Japan)

    1996-10-28

    In order to discuss effects of lithium iodide (LiI) doping on condensation structure of brown coals during heating, spectral changes were measured by using an in-situ FT-IR. It was found that the LiI doping accelerates weight reduction due to heating, and the doping effect is affected by coal structure. Both of Loy Yang (LY) coal and its LiI doped coal (DLY) had absorption intensity of the FT-IR spectra decreased with rising temperature, and the absorption center belonging to an OH group shows different shifts between the LY and DLY coals. This indicates that the LiI doping has affected the change in hydrogen bonding patterns associated with heating. Both of South Banko (SB) and LY coals had the absorption spectral intensity in the OH group decreased as the weight reduction (conversion) rate increased. Reduction in the OH groups associated with heating is caused by volatilization and condensation reaction in light-gravity fraction. However, in the case of equal conversion rate, the LiI doped coal shows higher spectral intensity than the original coal, with the LiI doping suppressing reduction in the OH groups. It appears that the doping suppresses the condensation reaction between the OH groups. 2 refs., 6 figs., 1 tab.

  11. Development of basic engineering to investigate dust prevention methods in the mechanised winning of thin coal seams. Proyecto de desarrollo de la ingenieria basica para la investigacion de metodos de prevencion del pulvo en el arranque mecanizado de capas estrechas de carbon

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Fidalgo, M.; Alvarez Santullano, L.; Eguidazu Pujades, J.L.; Gonzalez del Valle, S.; Cordera Fernandez, J.V.; Arriba de la Iglesia, J.

    1990-02-01

    The article concerns research work carried out jointly by HUNOSA and the National Institute of Silicosis on dust prevention on mechanised faces where thin seams are cut by shearers with a drum diameter of less than 600 mm. Under these conditions, it is not possible to use the conventional dust suppression systems employed for high-output shearers with larger drum diameters where the large quantities of sprayed water are easily absorbed by the coal. 11 figs., 1 tab.

  12. Modeling and simulation of strata movement for protective seam mining with large interburden

    Institute of Scientific and Technical Information of China (English)

    SONG Chang-sheng; LI De-hai; LI Hua-min

    2009-01-01

    Based on simulated material scale modeling and numerical simulation,the pro-tective seam mining method was conducted at one coal mine.After extracting the No.15 seam,the overlying strata movement and the deformation of the No.9-10 protected seam were studied.The experiment results show that it is feasible to destress the protected seams with large interburden thickness.When the face had advanced 200 m from the setup room,the No.9-10 seam was fully destressed,resulting in easy gas drainage in the destressed zone.Recommendations on mining sequence of multiple seams mining in the same coal areas were made.

  13. Entry roof truss-bolt system test under the gob of contiguous seams

    Institute of Scientific and Technical Information of China (English)

    LIAN Chuan-jie; XU Wei-ya; WANG Ya-jie

    2007-01-01

    Roof bolt support system has been widely applied in the No.7.9 seam in Caozhuang coal mine.However,it has not been able to be applied in the NO.10-2 seam since the small interburden(2m)between NO.9 and NO.10-2 seam.The NO.9 and NO.10-2 seams are contiguous seams.The NO.9 seam has been mined out and the NO.10-2 seam will be mined under the gob of the NO.9 seam.The roof strata of the NO.10-2 seam may have been weakened and fractured due to the shear failure caused by the NO.9 seam mining activities.The steel beam sets spaced at 0.8 m have been used to support the entry of the NO.10-2 seam.In order to speed up the advance rate and cut entry development cost,a test area,using roof bolt in conjunction with truss-system,was successfully conducted.This paper presents the support system design,application of designed system,and the test results.Test results provide a cheaper,quicker,and safer way to support entry for the No.10-2 seam.

  14. Research results of geotechnical properties of soils at the Podkrušnohorská výsypka dump in Sokolov brown coal field

    OpenAIRE

    Milan MIKOLÁŠ; Štrejbar, Martin; Stavinoha, Josef; Čermák, Ondřej

    2013-01-01

    Open pit brown coal mining in the Sokolov coal field has been suffering with the lack of a space for overburden rocks dumping from its very beginning. The Podkrušnohorská výsypka dump is situated in a geomorphologically highly broken landscape at the Krušné Hory Mountains foot and northern part of Sokolov Basin divide. Dump rock consists of tuffaceous clays vith minimal specific resistance values QST = 0.5 - 1.0 MPa and cypric clays with minimal specific resistance values QST =...

  15. Coal Seam Group A Floor Limestone Water Numerical Simulation Analysis in Panbei Coalmine, Huainan%淮南潘北煤矿A组煤层底板灰岩水数值模拟分析

    Institute of Scientific and Technical Information of China (English)

    刘林; 施安才; 许光泉

    2013-01-01

    The Panbei coalmine is situated at the north limb of the Panji anticline, has developed faults and fissures with different scales in the area and dissected limestone aquifers at different depths. Thereinto, the Taiyuan Formation C2I limestone aquifer directly impact the safe working of coal seam group A. Through dewatering test, large amount basic test data have been obtained. On these grounds, hydrogeological conditions have been analyzed, hydrogeological conceptual model and mathematical model established, and used main recovery and main dewatering as the model identification and verification stages. The result has demonstrated that: the Taiyuan Formation C2I limestone aquifer in the minefield is anisotropic, boundary condition is complex, and faults within the aquifer have different water transmissibility and resisting property. In local sectors the aquifer has hydraulic connection with Ordovician, Cambrian limestone aquifers and faults F1 and DF1 in limestone outcrop area are all water conducted faults verified. The study can provide scientific basis in forward safe mining of coal seam group A and limestone water control.%潘北矿位于潘集背斜北翼,区内发育了不同尺度断层和裂隙,且切割了不同深度的灰岩含水层.其中,太原组C2Ⅰ组灰岩含水层,直接影响A组煤层安全开采.通过放水试验,获得大量基础试验数据,分析了水文地质条件,建立了水文地质概念模型及数学模型,并采用总恢复和总放水作为模型的识别和验证阶段,结果表明:井田内太原组C2Ⅰ灰岩含水层为非均质性,边界条件是复杂的,含水层内部的断层具有不同程度导、隔水性等;并验证了在局部地段与奥陶系、寒武系灰岩含水层之间存在水力联系,以及灰岩露头区中F1、DF1均为导水断层等,为下一步A组煤层安全开采,防治灰岩水提供科学依据.

  16. COAL GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20091159 Gao Yan(No.3 Prospecting Team of Anhui Bureau of Coal Geology,Suzhou 234000,China) Effect of Depositional Environment of Coal-Bearing Stratum on Major Coal Seams in Suntan Coalmine,Anhui Province(Geology of Anhui,ISSN 1005- 6157,CN34-1111/P,18(2),2008,p.114 -117,5 illus.,1 ref.,with English abstract)

  17. 近距离煤层群倾向穿层钻孔合理布孔参数研究∗%Study on reasonable hole arrangement parameters of inclining layer-through borehole in close distance coal seam group

    Institute of Scientific and Technical Information of China (English)

    苏伟伟; 王兆丰; 陈向军

    2015-01-01

    为了解决新源煤矿在近距离煤层群赋存条件下采用倾向穿层钻孔抽采邻近煤(岩)层卸压瓦斯,抽采瓦斯浓度低,抽采率不达标,回采工作面上隅角瓦斯超限严重等问题。通过采用UDEC软件模拟采动覆岩移动破坏规律,获得开采2号煤层时上覆岩层裂隙带范围9~16m,确定倾向穿层钻孔合理布孔参数,钻孔倾角:21°~26°,孔深:44~47m。经在2219工作面试验考察,与原始参数钻孔抽采效果相比,钻孔平均瓦斯抽采浓度增加6倍多,抽采纯量增加15倍多,有效抽采距离增加3倍多,倾向穿层钻孔抽采率从20%提高到56.8%,回采期间上隅角瓦斯浓度能够控制在0.5%以下,保障了矿井安全生产。%In order to solve the problems that the gas extraction concentration was low, the extraction rate could not meet the standard and the gas exceeded the limit seriously in the upper corner of the working face in Xinyuan mine, which adopted the inclining layer-through borehole to extract the relief gas from adjacent seams under the geological condition of close distance coal seam group, the movement and damage rules of overlying strata were simulated by using UDEC software, and the range of fractured zone in overlying strata when mining No. 2 coal seam was 9 ~16m. The reasonable hole arrangement parameters of inclining layer-through borehole were determined, the inclina-tion of borehole was 21°-26°, and the depth of borehole was 44-47m. Through the experimental investigation in the 2219 working face, compared with the gas extraction effect of original parameter borehole, the average gas extrac-tion concentration increased more than 6 times, the gas extraction amount increased more than 15 times, and the ef-fective gas extraction distance increased more than 3 times. The extraction rate of inclining layer-through borehole improved from 20% to 56 . 8%, and the gas concentration in the upper corner could be controlled within 0 . 5%, so as to ensure

  18. Draft Genome Sequence of Bacillus pumilus Fairview, an Isolate Recovered from a Microbial Methanogenic Enrichment of Coal Seam Gas Formation Water from Queensland, Australia.

    Science.gov (United States)

    Vockler, Cassandra J; Greenfield, Paul; Tran-Dinh, Nai; Midgley, David J

    2014-04-17

    Despite its global abundance, Bacillus pumilus is poorly studied. The Fairview strain was obtained from a methanogenic anaerobic coal digester. The draft genome sequence was 3.8 Mbp long and contained 3,890 protein-coding genes. Like the SAFR-032 strain, it includes B. pumilus-specific proteins that likely confer enhanced resistance to environmental stresses.

  19. Stability tables for opencast mining of coal and sedimentary deposits in inclined seams. Abacos de estabilidad para mineria de carbon y sedimentaria a cielo abierto con capas inclinadas

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, F.J.; Granda, J.R.; Sarti, A.

    1985-01-01

    The six chapters of the book cover the following aspects of strata control in surface mining: design of opencast coal sites; parameters for the geomechanical design of opencast sites; methods for calculating slope stability; calculating the stability of spoil tips with a fractured cement base; calculation of stripping ratios; and stability tables.

  20. “三软”煤层水力冲孔卸压增透技术研究%Study on pressure releasing and permeability improving technology with hydraulic flushing in “three soft”coal seam

    Institute of Scientific and Technical Information of China (English)

    何志龙; 孙谦; 宋大钊; 高勤琼

    2015-01-01

    针对糯东煤矿“三软”高瓦斯低透气性煤层易流变、难抽采的问题,提出了底板巷道穿层水力冲孔卸压增透技术,并在糯东煤矿11702掘进工作面进行了现场试验。结果表明:冲孔后比冲孔前抽采瓦斯浓度上升3.4倍,瓦斯抽采流量增加4.4倍,炮掘工作面回风流中的瓦斯(体积分数)由冲孔前0.8%的超限预警状态变成冲孔后的0.4%的安全范围,水力冲孔技术应用效果显著,在糯东煤矿取得了良好的卸压增透效果。%To solve the problem of easy rheology and hard drainage in"three soft"coal seam with high gas concentration and low permeability in Nuodong coal mine,the pressure releasing and permeability improving technology with hydraulic flushing in floor gateway was proposed,and corresponding field test at the No.11702 heading face of Nuodong coal mine was carried out.The re-sults show that the drained gas concentration after hydraulic flushing is 3.4 times as that without hydraulic flushing and the gas flow rate is increased by 4.4 times;and the gas concentration at the blasting working face changes from 0.8% (overrun warning state,before hydraulic flushing)to 0.4% (safety state,after hydraulic flushing).The application of hydraulic flushing technolo-gy is more effective and remarkable in releasing pressure and improving permeability in Nuodong coal mine.

  1. Regional Outburst Prevention Test by Coal Seam Infusion Humidification and Permeation Fluid Mechanics Numerical Solution of Parameter Optimization%煤层注水增湿区域防突试验与参数优化的渗流力学数值解

    Institute of Scientific and Technical Information of China (English)

    李志强; 唐旭; 王兆丰

    2012-01-01

    为增强煤体黏结力和塑性并抑制瓦斯放散强度,以达到稳定煤体区域防突的目的。以重庆天府三矿K4煤层为目标区,进行了低温液氮孔隙结构分析实验、煤体润湿性实验和湿润边角测定实验。分析了煤层注水可行性。实验表明:煤体孔隙多数为平板状开放孔,润湿边角〈90°,吸水性强。具注水可行性。在重庆天府矿业公司850m深井底板岩巷进行了煤体扩孔卸压后的高压注水试验,测定了卸压后煤体透水性系数。建立了煤层注水的径向渗流力学方程,以实测数据为基础,优化计算了合理的注水压力、时间、注水半径等动态时空参数。%To strengthen the coal bonding force and plasticity, inhibit the gas irradiation intensity and achieve the purposes of stabilizing the coal body and regional outburst prevention, taking K4 coal seam of Tianfu No. 3 coal mine in Chongqing as target area, cryogenic liquid nitrogen pore structure analysis experiments, coal wettability experiments and moist comers measurement experiment were carried out, and the feasibility of coal seam infusion was analyzed. The experiments showed that the majority of coal pores were plate - shaped open holes with strong water absorption, wetting corners were less than 90~and had the feasibility of water infusion. The high - pressure infusion test was carried out in the floor rock of deep shaft of Chongqing Tianfu mining company with depth of 850 m after the relief of the coal body reaming, and coal permeability coefficient was measured after relief. Based on measured data, the radial flow mechanics equation of coal seam infusion was established, and the dynamic spatial and temporal parameters of water infusion pressure, time, and infusion radius were optimized and calculated.

  2. A Discussion on Coal Seam Methane Carbon Isotope Distribution Features and Gas Genetic Classification in China%我国煤层甲烷碳同位素分布特征与瓦斯成因类型划分探讨

    Institute of Scientific and Technical Information of China (English)

    孙四清; 李贵红; 安鸿涛

    2012-01-01

    Based on 170 plus sets of coal seam methane carbon isotope measured results, analyzed 513Ci value distribution features of Chinese coal seam gas, discussed its genetic classification. The studied results have demonstrated that: the distribution range of SaCi value is within - 73.3%e-27.3%e, the value increasing along with the degree of coal metamorphism. After the anthracite stage, the value variations tend to be stable, fluctuating about -35%o or so. According to varying relations between coal seam methane carbon isotope and coal ranks, taking maximum reflectance of vitrinite as indicator, classified Chinese coal seam gas genesis into 3 major types: secondary biogenetic, mixing origin and thermogenetic gases, and pointed out gas genetic types of part coal mining areas in China.%以170余组煤层甲烷碳同位素测定结果为依据,分析了我国煤层瓦斯的δ13C1值分布特征,探讨了瓦斯成因类型划分,研究结果显示:δ13C1值分布范围为-73.3‰~-27.3‰,δ13C1值随煤的变质程度的增加总体增大,无烟煤阶段以后,δ13C1的变化趋于平稳,在-35‰上下波动;根据煤层甲烷碳同位素与煤级之间的变化关系,以煤的最大镜质体反射率作为指标,将我国煤层瓦斯成因分为次生生物成因气、混合成因气和热成因气三大类,并指出了我国部分煤矿区的瓦斯成因类型.

  3. 井下杂散电流及接缝电阻集成测试仪的设计%Design of measuring instrument of stray current and seaming resistance of underground traction network of coal mines

    Institute of Scientific and Technical Information of China (English)

    王克军; 程辉; 付立华

    2012-01-01

    井下杂散电流是指在井下架线电机车的运输系统中任何不按指定通路流动的电流,它是随机事件,而且是连续变化的量,是影响煤矿安全的主要因素之一.对井下杂散电流的测试是指导井下架线、防治杂散电流的前提,详细介绍了集成杂散电流及接缝电阻测试仪的设计原理和实现方法,并给出了主要的硬件电路和软件主流程图.%Stray current flow is defined as the flows in route in designated the wiring of electric locomotive transportation system. Stray current is a random event and changes continuously. Stray current is one of the elements that affect the safety of coal mines. To measure stray current is the prerequisite to direct wiring of traction network and prevention of stray current. The design principles and realization methods of measuring meter of stray current and seaming resistance between two rails in detail is introduced, and the main hardware schematic circuit diagram and software main flow chart are given.

  4. Investigation, development and demonstration of an integrally mechanised method of exploitation in coal seams with dips of between 40 and 60 degrees. Investigacion, desarrollo y demonstracion de un metodo de explotacion integramente mecanizado en capas de carbon con inclinacion entre 40 y 60 grados

    Energy Technology Data Exchange (ETDEWEB)

    Lago, R.; Margereto, J.; Luque, V.; Fuente, A.; Saez, E.

    1989-01-01

    The integral mechanization of semivertical and vertical coals seams with inclinations of 40-60{degree} poses a problem which has not yet been satisfactorily solved. The aim of this project was to find equipment which helps to solve the problem. In cooperation with Westfalia-Luenen GmbH and Mackina Westfalia, 14 supports were designed and constructed for installation in an experimental face with a dip of 57{degree} and mean thickness of 1.58m, located at Hunosa's Pozo Ma Luisa mine. The movement of the filling for different seam inclinations was also investigated, with the help of a scale model, a number of measurements on site and a computer program simulating its behaviour. This report describes the mining method used during the experiment and draws conclusions which permit the determination of conditions for future use of both the method and the equipment, as well as the features of the face to which these can be applied. The main conclusions are as follows: the method is feasible in seams ranging from between 0.90 and 2.20 m, with medium and even bad roofs, appropriate walls and minimum 500-600m length; with or without filling, failure of a considerable part of the roof occurs after the passing of the supports and for this reason a retreating method is recommended; covering of the roof must be increased; supports must be lightened and shortened and for seams of over 70{degree} inclination, other modifications are probably needed.

  5. Occupational exposure to rubber vulcanization products during repair of rubber conveyor belts in a brown coal mine

    Energy Technology Data Exchange (ETDEWEB)

    Gromiec, J.P.; Wesolowski, W.; Brzeznicki, S.; Wroblewska-Jakubowska, K.; Kucharska, M. [Nofer Institute of Occupational Medicine, Lodz (Poland)

    2002-12-01

    This study was carried out to identify chemical substances and measure their air concentrations in the repair shop of a brown coal mine in which damaged rubber conveyor belts were repaired. GC-MS and HPLC analysis of stationary air samples resulted in identification of aliphatic and aromatic hydrocarbons to C{sub 12}, PAHs, alcohols, phenols, ketones, heterocyclic nitrogen and sulfur compounds. Quantitative evaluation of occupational exposure included determination of organic compound vapours collected on charcoal (GC-MSD), polycyclic aromatic hydrocarbons (HPLC), N-nitrosoamines and other amines (GC-NPD) and DNPH derivatives of aldehydes (HPLC) in the breathing zone of workers representing all job titles. The concentrations of investigated compounds were very low. Carcinogenic substances: N-nitrosoamines, benzene, and PAHs were not present in workroom air in concentrations exceeding limits of detection of the analytical methods being applied; concentrations of methylisobutylketone, tetrachloroethylene, naphtha, aromatic hydrocarbons, phthalates and aldehydes were much lower than the respective occupational exposure limit values. The results indicate much lower exposure than that reported in the production of tyres and other fabricated rubber products.

  6. Groundwater flowing the forefield of the CSA mine (North Bohemian Brown Coal Basin in the Czech Republic)

    Energy Technology Data Exchange (ETDEWEB)

    Zizka, L.; Halir, J. [Brown Coal Research Inst., Most (Czech Republic)

    2010-07-01

    The North Bohemian Brown Coal Basin is home to one of the largest active open cast mines in the Czech Republic. Groundwater flow in the quaternary sediments is causing stability problems in the upper overburden at the mine. A 3-D geological model was used to simulate groundwater flow in the area. The lithological characteristics and hydrogeological conditions of the mine were also considered in order to identify areas that may pose risks during the extraction of mineral resources. The simulation focused on the characterization of the quaternary and crystalline aquifer collectors located in the region of the mine. The study showed that groundwater flow is influenced by the configuration of the quaternary floor, as well as by the deposition and character of the basin sediments and crystalline rocks. The donation area corresponds with the mountain slopes. Groundwater flow is influenced by disruptions in the crystalline roof with quaternary sediments. The quaternary aquifer will be dewatered in order to ensure the future safety of the mine. 3 refs., 2 figs.

  7. Power plant ash and slag waste management technological direction when Kansk-Achinsk brown coal is burned

    Directory of Open Access Journals (Sweden)

    Lihach Snejana A.

    2017-01-01

    Full Text Available Today resource efficiency technology development in all industries where conventional raw material is being replaced by local natural resources and industrial waste is an essential matter. Along with that most producing operations are overload with wide range of waste produced during technological process. Thermal power stations are real world evidence. Their main waste is ash and slag which accumulated in great amounts in often overfull ash dumps. The goal of present work is to find perspective ash dump waste utilization methods. The study will be based on experimentally obtained data: elementary compound and properties of Kansk-Achinsk brown coal. Research methods: experimental, chemical silicate analysis, mineralogical forms identification within samples by using ASM X-ray diffraction analysis. Experiments resulted with the following conclusions: silica is ash main component, and ash has the form of ore concentrate analogy in a number of elements. We think that ASM main properties which make it useful for utilization are: high content of calcium oxide; high ash sorption properties; ASM radiation safety class which makes them safe to be used in materials, goods, and structures production for residence and public buildings construction and reconstruction; sufficiently high content of individual elements.

  8. The coal-bearing Cenozoic As Pontes Basin (northwestern Spain): geological influence on coal characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, L.; Hagemann, H.W.; Pickel, W.; Saez, A. [Universitat de Barcelona, Barcelona (Spain). Dept. de Geologia Dinamica, Geofisica i Paleontologia

    1995-03-01

    Lignite deposits in the Cenozoic As Pontes strike-slip basin (northwestern Spain) were formed as a function of specific paleoclimatic conditions and tectonic evolution of the basin. During the early evolutionary stages, the presence of active normal faults and thrusts inside the basin resulted in two subbasins with distinct differences in sedimentary records, with respect to lignite seam occurrence, thickness, areal extent and lithotype development. In contrast, during the late evolutionary stages the basin was not split and a more homogeneous sedimentary record in terms of coal seam occurrence and lithotype characteristics developed. A total of 26 lignite samples, distributed along the basin infill, were analyzed by organic petrography and geochemistry. All are lignite B (ASTM). The lignites deposited during lower basin infill sedimentation (unit 1 and 2) are dark, matrix-rich, mainly huminitic brown coals, with minor bright, liptinitic-rich coal lithotypes. The dark huminitic coals in these units show sedimentological and paleontological evidence of lacustrine influence. Lignites in the upper basin infill (Unit 4) are almost exclusively matrix-rich, huminitic brown coals. The overall coal petrological data trend recorded from the lower to the upper basin infill units agrees with the stratigraphic and sedimentological data, which show a trend of increasingly drier conditions. Development of bright, liptinite-enriched lignite layers was widespread during the early basin evolutionary stages and was influenced by punctuated water-table oscillations. Sedimentological, petrological and organic geochemical data suggest that, although the paleoenvironments where peat deposition took place did not undergo dramatic changes, they were affected by distinguishable variations, linked mostly to the evolution of basin morphology and basin water balance. 52 refs., 8 figs., 3 tabs.

  9. 利用煤田测井曲线精细解释淮南某矿1煤层采区地质特征%Exquisite interpretation of geological features of No .1 coal seam mining area in a mine in Huainan by logging of coal field exploration

    Institute of Scientific and Technical Information of China (English)

    徐胜平; 云晓鸣; 汪宏志; 王轩

    2015-01-01

    In view of the situation of low utilization rate of logging data in coal exploration at present , the correlativity between geological physical property parameters and high relevancy logging property parameters is established through digitization and standardization of logging curve ,statistics and anal‐ysis on amplitude of curve parameters . Through obtaining property model of the single factor or multi‐factor ,the characteristic of gas storage in coal and rock stratum ,hydrogeological condition of stratum ,mechanical properties of rock and so on can be explained supplementarily .The interpretation results of No .1 coal seam in mining area of Huainan mining field show that the composite parameters obtained by comprehensive utilization of logging curve have an extremely high correlation with coal bed gas content and have a moderate correlation with tensile strength of coal seam roof ;the water characteristic in mining area obtained by referring Archie formula in oil has broadly matched with that by tunnel exposing .This method can provide a kind of effective means for use of logging data .%文章针对目前煤田测井曲线资料利用率偏低的情况,通过对测井曲线进行数字化、标准化,统计和分析曲线参数幅值,建立地质物理性质参数与相关度高的测井曲线属性参数之间相关关系,获得测井曲线参数单因素或多因素属性模型,可对岩煤层储气特征、岩层水文地质条件及岩石力学性质等特征进行辅助解释。淮南矿区1煤层采区解释结果表明:综合利用测井曲线分别求得的复合参数与煤层瓦斯含气量之间具有极高相关性,与煤层顶板岩石抗压强度具有中度相关性;借鉴A rchie公式所求得的采区岩层赋水性与巷道揭露的赋水特征基本一致。该方法可为测井曲线资料再利用提供一种有效手段。

  10. 云南洛旺煤矿区上二叠统主采煤层煤质特征及其影响因素%Coal Quality Characteristics and Impacting Factors of Upper Permian Main Mineable Coal Seam in Luowang Coalmine Area, Yunnan

    Institute of Scientific and Technical Information of China (English)

    孙顺新

    2014-01-01

    The Luowang coalmine area is an important coal production area in Yunnan. Coal rank in the area is mainly meager coal, lo-cally anthracite. Based on geological exploration and coal quality tested data, systematically analyzed coal quality characteristics of main mineable coal seam C5 and varying pattern, discussed its impacting geological factors. The result has shown:sulfur content of coal C5 in the area is gradually increasing from southwest to northeast, ash content deceasing from east to west. This is due to sedimentary environment variation of limnic basin to paralic basin from west to east. Horizontally, coal rank in the middle part is anthracite III, grad-ually changed into meager coal toward both east and west ends. Analysis thinks that the hypozonal metamorphism is the main causa-tion, while coal seam buried depth in middle part is deeper than both east and west ends, thus degree of metamorphism is relatively high. Speculation based on structural conditions, the paulopost dynamic metamorphism has made for middle part degree of metamor-phism deepening a certain extent.%洛旺煤矿区是云南重要的煤产地,煤类以贫煤为主,局部为无烟煤。根据地质勘查成果及煤质测试资料,系统分析了该区主采煤层C5煤层的煤质特征及其变化规律,探讨了影响煤质变化的地质因素。结果表明:区内C5煤层硫分由西南向东北逐渐增大,灰分产率自东向西逐渐降低,这一规律主要受自西向东陆相到海陆交互相沉积环境变化的控制。在平面上煤类表现为煤矿区中部为无烟煤三号,东西两端逐渐变为贫煤,分析认为深成变质作用是造成煤类变化的主要原因。矿区中部煤层埋深较东、西两端大,煤变质程度相对高,根据构造条件推测,后期的动力变质作用对矿区中部煤变质程度的加深起了一定的促进作用。

  11. In-situ coal gasification as a progressive coal utilization method

    Energy Technology Data Exchange (ETDEWEB)

    Petrenko, E.V.; Saltykov, I.F.

    1988-02-01

    Describes the Podzemgaz coal gasification station at Angren that was put into operation in 1961. It exploits a 15 m thick and 120-250 m deep seam of brown coal. Technology of in-situ coal gasification is described and its results are compared in regard to cost and efficiency with the results of conventional surface mining. Air blowing is used for most in-situ coal gasification in USSR. Trials using air enriched in oxygen for this purpose were conducted in 1953 and 1957 but did not find wider application. A station using oxygen enrichment technology is planned for Angren at the Apartak section, as cheaper oxygen production methods have emerged. A new concept for in-situ coal gasification using membrane technology (molecular sieves) is set out. This technology assures total chemical and power utilization of coal, yielding not only coal gas but also liquid nitrogen, hydrogen, a mixture of both these gases for ammonia production, and carbonic acid. Prospective site selection for in-situ coal gasification stations is discussed and conditions required for the respective coalfields are outlined.

  12. 突出煤层炮掘工作面煤与瓦斯突出防治技术与实践%Technical Measure and Practice in Prevention and Control of Coal and Gas Outburst in Blasting Face of Outburst Coal Seam

    Institute of Scientific and Technical Information of China (English)

    韦善阳; 崔永国; 张保印; 刘闯; 黄励新

    2012-01-01

    突出煤层炮掘工作面煤与瓦斯突出防治是防突工作的重点和难点。平煤十矿在己15—24080机巷炮掘过程中严格执行“四位一体”防突措施和“一炮三检制”及“三人联锁放炮制”,并与加强区域和局部防突措施相结合,保障了掘进过程中的安全,充分发挥了炮掘的优势,在掘进的1800多米机巷中,效检值q和s始终在指标值之下,没有发生安全事故,防突效果良好。%The prevention and control of coal and gas outburst in blasting face of outburst coal seam are the key & hard parts of coal and gas outburst control. During the 已 15 - 24080 coal roadway drivage of Pingdingshan ten shares of Mine," Four in One" integrated control measures and the two systems of blasting were implemented strictly, and in some areas and local places the prevention and control measures of coal and gas outburst were enhanced,which assured the safety of roadway drivage ande mad use of advantage of blasting drivage. During driving the 1800 m 15 -24080 machine roadway, the detected q and s values were lower than the index values, no safety accidents occurred, with good outburst prevention and control effect.

  13. Efficient Drilling Technology of Long Directional Borehole for Gas Drainage in the Medium Hard Coal Seam%中硬煤层瓦斯抽采定向长钻孔高效钻进工艺

    Institute of Scientific and Technical Information of China (English)

    杨虎伟; 许超; 董萌萌; 赵建国; 牟培英; 康奇岳

    2014-01-01

    The gas drainage with boreholes is the most direct and effective means for gas control.According to the principle of directional drilling technology in coal mine underground, an effective drilling technology applicable to medium hard coal seam is put forward to realize effective long directional drilling by combining compound drilling technology and directional drilling technology in coal mine underground.The field test proves that this method can make the borehole wall smooth, prevent pump suffocation and sticking, reduce the accident processing time and improve the successful drilling rate and drilling efficiency.By the application of this technology, average ROP increases by 26.8%compared with the conventional directional drilling.%钻孔抽采瓦斯是治理瓦斯最直接有效的手段。根据煤矿井下本煤层定向钻进技术原理,提出一种适用于中硬煤层定向长钻孔的高效钻进工艺,该工艺是将复合钻进技术与煤矿井下定向钻进技术相结合实现定向长钻孔高效钻进的一种钻进方法。通过现场试验证明,该方法能使钻孔孔壁平滑,防止憋泵、卡钻,减少事故处理时间,提高钻孔成功率和钻进效率。经分析,使用该技术后,与常规定向钻进相比,平均机械钻速提高了26.8%,该技术为今后煤矿井下定向钻进技术的推广提供了新思路。

  14. 平朔矿区煤中矿物分布及赋存特征研究%Study on Mineral Distribution and Deposition Features of Coal Seam in Pingshuo Mining Area

    Institute of Scientific and Technical Information of China (English)

    白向飞; 王越

    2013-01-01

    In order to study the ash behavior features of coal in Pingshuo Mining Area and to provide the basis to the pollution control of the trace elements,a reflected-light microscope,scanning electron microscope and other means were applied to study the distribution and deposition features of the clay mineral,aluminium hydroxide mineral,calcite,siderite,pyrite and other minerals in No.4 coal seam of Pingshuo Mining Area.The paper also had a deep analysis on the distribution features of the dispersed minerals and trace elements in the clay mineral in coal of Pingshuo Mining Area as well as the paragenetic and metasomatism function between each mineral.The study showed that the clay mineral in coal of Pingshuo Mining Area mainly would have two different optical properties.The Si/Al atomic ratio in two clay minerals was close and there was a small difference in the mineral composition.The kaolinite was the mineral mainly in the composition of the clay.The aluminium hydroxide mineral was the typical mineral type in Permian coal of Pingshuo Mining Area.In comparison with coal in other areas,Al203 was the important sources in the ash and had a close paragenetic with calcite,pyrite and other minerals.%为研究平朔矿区煤中煤灰行为特性,为微量元素污染控制提供依据,采用反射偏光显微镜和扫描电镜等手段,对平朔矿区4号煤层中黏土矿物、铝的氢氧化物矿物、方解石、菱铁矿和黄铁矿等矿物的分布和赋存特征进行了研究,同时深入分析了平朔矿区煤中黏土矿物中分散矿物及微量元素的分布特征,以及各种矿物之间的共生、交代作用.研究表明,平朔矿区煤中的黏土矿物主要呈现2种不同的光学性质,但2种黏土矿物中的Si/Al原子比相近,矿物成分差别不大,均以高岭石黏土矿物为主;铝的氢氧化物矿物是平朔二叠纪煤中有代表性的矿物类型,在其他地区煤中比较少见,是煤灰中Al203的重要来源,且与方解石、黄铁矿等矿物密切共生.

  15. Support of the business management of opencast brown coal mining with an enhanced variability of deposits based on mine surveyoral data management; Unterstuetzung der Betriebsfuehrung von Braunkohlentagebauen mit hoher Lagerstaettenvariabilitaet auf Grundlage des markscheiderischen Datenmanagements

    Energy Technology Data Exchange (ETDEWEB)

    Knipfer, Anja [Mitteldeutsche Braunkohlengesellschaft mbH, Zeitz (Germany). GIS/Risswerkfuehrung

    2012-04-15

    A variable manifestation of the deposit is a particular challenge for the operational management for the continuous supply of coal in a specified range. Mitteldeutsche Braunkohlengesellschaft mbH (Zeitz, Federal Republic of Germany) supports the planning and production process by a GNSS controlled dredging. The storage of all operating conditions at the database level is the basis for the different evaluations. The verification of the data separaed by waste and coal enables a statement to the recoverability of the seams under consideration of a impact mapping and production data. This is an aid for the continuous improvement of the extraction planning and management.

  16. Extracting a very thick seam at the Stara Jama mine in Yugoslavia

    Energy Technology Data Exchange (ETDEWEB)

    Bijelic, V.

    1986-08-01

    With the general call for a high degree of exploitation of coal deposits, the complete extraction of thick seams is increasingly growing in importance. The following article shows, that the solution of this problem nowadays with fully mechanised longwall installations, as are available at the Stara Jama mine in Zenica, Yugoslavia, can be regarded as an example for the complete extraction of thick coal seams. Since the installation was first put into operation in 1978, the production results have been considerably improved upon.

  17. Flora in the Soton and Entrerregueras series of coal seams in Brana del Rio in the Central Asturian coalfield, NW Spain

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Vazquez, C.

    1986-01-01

    The flora of the carboniferous successions of the Central Asturian Coalfield is poorly known due to the lack of detailed systematic studies. This work is the result of paleobotanic study in the most important fossiliferous levels of the Soton and Entrerregueras coal members. Thirty-eight different species are listed together with their age and stratigraphic position. The presence of levels containing marine fauna alternating with plant remains levels, shows the apparent disagreement between the ages of the marine and continental scales. 17 refs., 2 plts., 2 tabs.

  18. Cooperative evaluation of San Juan Basin, Phillips Petroleum Company, openhole well recompletion efforts. Topical report, May 1, 1993-January 15, 1994. Western cretaceous coal seam project

    Energy Technology Data Exchange (ETDEWEB)

    Mavor, M.J.; Logan, T.L.; Robinson, J.R.

    1995-07-01

    Over 920 San Juan Basin Fruitland Formation openhole coal gas wells have been drilled. Significantly greater gas deliverabilty is possible if substandard productivity can be improved. Two low productivity wells were recompleted. The first was recompleted using conventional and high pressure dynamic openhole procedures. The second was recompleted using hydraulic fracturing techniques. None of the stimulation techniques increased the reservoir deliverablity above that achieved by the original openhole completion. Hydraulic fracturing damaged the near-wall permeability and productivity of the no. 234 well. Extensive testing and production logging were performed to support the conclusions.

  19. The 2000/60/EC Water Framework Directive and the Flooding of the Brown Coal Meirama Open Pit (NW Spain)

    Science.gov (United States)

    Delgado, J.; Juncosa, R.

    2009-04-01

    Coal mining in Galicia (NW Spain) has been an important activity which came to an end in December, 2007. Hence, for different reasons, the two large brown coal mines in Galicia (the As Pontes mine, run by ENDESA GENERACIÓN, and the Meirama mine, owned by Lignitos de Meirama, S.A., LIMEISA), have started closure procedures, both of which are considering the flooding of the mine pits to create two large lakes (~8 km2 in As Pontes and ~2 km2 in Meirama). They will be unique in Galicia, a nearly lake-free territory. An important point to consider as regards the flooding of the lignite mine pits in Galicia is how the process of the creation of a body of artificial water will adapt to the strict legal demands put forth in the Water Framework Directive. This problem has been carefully examined by different authors in other countries and it raises the question of the need to adapt sampling surveys to monitor a number of key parameters -priority substances, physical and chemical parameters, biological indicators, etc.- that cannot be overlooked. Flooding, in both cases consider the preferential entrance into the mine holes of river-diverted surface waters, in detriment of ground waters in order to minimize acidic inputs. Although both mines are located in the same hydraulic demarcation (i.e. administrative units that, in Spain, are in charge of the public administration and the enforcement of natural water-related laws) the problems facing the corresponding mine managers are different. In the case of Meirama, the mine hole covers the upper third part of the Barcés river catchment, which is a major source of water for the Cecebre reservoir. That reservoir constitutes the only supply of drinking water for the city of A Coruña (~250.000 inhabitants) and its surrounding towns. In this contribution we will discuss how mine managers and the administration have addressed the uncertainties derived from the implementation of the Water Framework Directive in the particular case of

  20. Bare face red-brown bricks manufactured with fly ash from the Narcea (Asturias Coal Power Plan

    Directory of Open Access Journals (Sweden)

    Ayesta, G.

    1999-12-01

    Full Text Available Fly ash, from the Coal Power Plant of Narcea (Asturias, has been used to determine its possible use as a raw material in the bare face red-brown brick manufacture. The correct mould of a ceramic material demands a paste with an adequate plasticity. So, the optimum compositions of humidity, lubricant (talc and binder (white dextrin have been investigated. The samples were made by compressing paste into a mould using varying values of pressure and boiling temperature once the cooling speed had been established. Finally, the cooked pieces were submitted to trials demanded by the Basic Construction Norm, to see if they met the required specifications concerning Water Absorption, Suction, Contraction, Resistance to Freezing, Efflorescence and Compressive Strength.

    Se caracterizan las cenizas volantes de la Central Térmica del Narcea (Asturias para determinar su utilización como materia prima en la obtención de ladrillos cara vista. El moldeo correcto de una pieza cerámica exige trabajar una pasta con una adecuada plasticidad, para ello se investiga cuál ha de ser la composición óptima de la misma, en cuanto a: humedad, cantidad de lubricante (talco y de ligante (dextrina blanca. El conformado de las piezas o ladrillos se realiza por prensado, utilizando distintos valores de presión, así como la temperatura de cocción, una vez establecida la velocidad de enfriamiento. Finalmente, las piezas cocidas se someten a los ensayos exigidos por la Norma Básica de Edificación, para ver si cumplen las especificaciones requeridas en cuanto a: Absorción de agua. Succión, Contracción, Heladicidad, Eflorescencia y Resistencia a la compresión.

  1. 伊犁盆地ZK0161井褐煤中铀及其它元素的地球化学研究%Geochemistry study of its uranium and other element of brown coal of ZK0161 well in Yili Basin

    Institute of Scientific and Technical Information of China (English)

    杨建业; 狄永强; 张卫国; 刘善德

    2011-01-01

    用数理统计的方法,对伊犁盆地洪海沟ZKO161井的中下侏罗统11、12号煤层中的铀等59种常量、微量元素的地球化学行为进行了初步探讨.认为元素在灰分的分布和元素在内在水分及固定碳中的分布大体呈互为相反数关系,而和元素-挥发分相关系数则呈同步性变化.ZK0161井煤中u以后生铀为主,分别以可溶态和有机吸附态或结合态形式出现在12号煤和11号煤顶部的煤中内在水和煤有机质中.%The research of geochemistry of 59 kinds constant elements and trace elements in brown coal of ZK0161 well, which located at Honghaigou area in Yili Basin of Xinjiang Uyghur Autonomous Region, China, was completed by means of mathematical statistics methods. The results show that the correlation coefficients of ash-elements is each or-ther's opposite number with one of inherent moisture, and has synchronous changes with one of volatile-elements. Uranium in coal of ZK0161 well is mainly epigenetic one and may be respectively in the form of soluble existed in the internal water and organic absorbed or organic phase existed in organic matter on the top of No. 11,12 coal seams.

  2. Comprehensive measurement of characteristics of deformation and failure of extra-thick coal seam floor induced by fully mechanized top-coal mining%特厚煤层综放采动底板变形破坏规律的综合实测

    Institute of Scientific and Technical Information of China (English)

    朱术云; 曹丁涛; 岳尊彩; 姜振泉; 赵连涛; 于旭磊

    2012-01-01

    为了探究兖州煤田兴隆庄煤矿特厚煤层综放开采对底板岩层的变形破坏规律,应用钻孔应变感应法和超声成像技术对该矿某综放工作面进行了综合实测,获得了底板下不同深度应变增量随工作面推进的变化曲线和工作面推进过程中不同深度钻孔超声成像图片资料。通过5个应变传感器监测数据和大量钻孔超声成像图片的关联对比分析,基本确定了该工作面采动底板扰动深度和矿压作用下支撑压力的影响范围。研究结果表明:①该工作面底板采动扰动深度约为19 m,具有较明显分带性,即可分为采动扰动破坏带和采动扰动变形带,带厚分别约为16 m和3 m;②采动扰动破坏带属于整体塑性变形,其强度条件已基本丧失,但采动扰动变形带仍以弹性变形为主,具有良好的承载条件和较强的抗渗强度;③采动矿压超前和滞后显现明显,其对底板影响程度具有由浅及深而减小的特征。该综合实测方法的成功应用不但为综放开采巷道支护、老空水防治等提供重要信息,而且对深部即将开采的下组煤能否安全带压采掘研究也将具有重要参考价值。%In order to study the characteristics of deformation and failure of fully mechanized top-coal seam floor under mining in Xinglongzhuang Coal Mine in Yanzhou Coal Field, comprehensive measurements are performed by means of the strain testing system and ultrasonic imaging technology in the fully mechanized top-coal working face, and the variation curves of strain increment and the ultrasonic imaging pictures at different depths are obtained in the monitoring boreholes with extending of the working face. Through the comprehensive comparison of monitoring data of five strain transducers and many hole wall pictures, the disturbance depth and underground pressure influence range are approximately ascertained. The results show that: (1) the disturbance depth of the coal seam

  3. Mechanical behavior investigation for floor rock stratum in the water-rich coal seam%含水煤层底板岩层力学性质分析:以小纪汗煤矿为例

    Institute of Scientific and Technical Information of China (English)

    李海龙; 白海波; 钱宏伟; 马丹; 许静

    2016-01-01

    在陕北榆林小纪汗煤矿实际建井开采过程中发现了煤层为矿井主充水含水层这种特殊的水文地质现象,为对这种特殊现象下底板岩层的力学性质进行分析,对现场底板岩样进行岩石矿物成分测试、岩石膨胀性测试及水作用下岩石强度弱化规律测试等一系列试验研究。研究发现:1)小纪汗煤矿煤层为裂隙含水层,且为矿井主充水含水层,底板岩层长时间受水侵蚀,岩体易于软化、变形,易造成岩层裂隙扩展及其稳定性破坏;2)底板岩样中含蒙脱石、伊利石等膨胀性矿物是底板岩层膨胀变形的微观影响因素;3)底板岩样浸水膨胀变形经过急速膨胀—变形缓慢—变形结束3个阶段,岩样浸水2 h 内的膨胀变形已占总变形量73.3%,浸水2~12 h,变形量占总变形量的24.7%,浸水12 h 后,试样基本不变形;4)岩样与水作用后其单轴抗压强度、弹性模量、劈裂抗拉强度随饱水时间的延长、含水率的增大而不断降低,总体呈指数关系递减;5)岩样浸水12 h后,岩石单轴抗压强度、弹性模量及抗拉强度降低值占总衰减值分别为71.6%,72.3%和65.4%,煤层裂隙水对底板岩层的侵蚀软化作用明显。%One special hydrogeologic phenomenon was found when building well drilling for Xiaoji-han mine located in Yulin city, north of Shaanxi province. The coal seam is a main aquifer to the geo-logic structure of the nearby area. Different tests including rock mineral composition test for floor rock samples, rock expansion test and the rock strength test under water pressure have been applied to find out the mechanical properties of the floor rock stratum under this special hydrogeologic phenomenon. The following conclusions have been drawn: 1) The coal seam of Xiaojihan mine is found out to be a fracture aquifer as well as a main aquifer. The floor rock has been exposed to water erosion for a long time, which

  4. Desulfurization and oxidation behavior of ultra-fine CaO particles prepared from brown coal; Kattan wo mochiite choseishita CaO chobiryushi no datsuryu tokusei to sanka tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Benjamin, G.; Roman, M.; Yamazaki, Y.; Abe, H.; Harano, Y.; Takarada, Y. [Gunma University, Gunma (Japan). Faculty of Engineering

    1996-10-28

    The effect of reaction temperature and oxygen concentration on the desulfurization and oxidation behavior of ion-exchanged brown coal by Ca as new desulfurizing agent was studied. In experiment, Yallourn coal was used for ion- exchange, and limestone produced in Tochigi prefecture was also used for comparative study. Ca-exchanged brown coal was prepared by agitating coal in Ca(OH)2 slurry for 24 hours. The desulfurization behavior of a desulfurizing agent was obtained by measuring H2S and sulfur compounds in outlet gas of a reactor, and the oxidation behavior by measuring SO2 emission in outlet gas after oxidation reaction. As the experimental result, CaO produced from Ca-exchanged brown coal offered the extremely high activity to desulfurization reaction in a temperature range of 850-950{degree}C as compared with limestone. Although the oxidation behavior was dependent on oxidation temperature and oxygen concentration, CaS obtained from Ca-exchanged brown coal was more rapidly converted to CaSO4 than limestone. 3 refs., 8 figs., 2 tabs.

  5. 松软煤层综放开采护巷煤柱合理宽度研究%Study on Ratinal Width of Protective Coal Pillar in Mining Gateway of Fully Mechanized Top Coal Caving Face in Soft Seam

    Institute of Scientific and Technical Information of China (English)

    韩玉林

    2011-01-01

    汾西新阳矿综放工作面煤柱留设大,为了减少煤柱宽度,提高采区采出率,基于极限平衡理论的分析方法,推导出计算煤柱宽度的表达式,结合煤柱强度与高宽比关系,设计煤柱宽由35m减少到25 m;采用连续自动采集装置,实测得煤柱侧支承压力范围为10~12 m,所设计煤柱宽大于2倍塑性区宽,理论计算与测试结果具有很好的一致性。现场监测结果表明:掘进期间,煤柱侧巷道顶板位移85 mm,两帮移近70 mm,顶板深部、浅部离层分别为8和10 mm;回采期间,顶板及两帮位移分别为105和90 mm,离层没有变化,煤柱和巷道都保持稳定,满足安全生产要求。%In the fully mechanized coal caving mining face of Fenxi Xinyang Mine,the coal pillar left for the coal mining face was large.In order to reduce the coal pillar width and improve the coal recovery rate of the coal mining face,base on the analysis method of the limit balance theory,the expression to calculate the coal pillar width was derived.With the relationship between the coal pillar strength and the high and wide ratio,the designed coal pillar width was as reduced from 35 m to 25 m.With the continued automatic sampling device,the actual measured data showed that the lateral support pressure scope of the coal pillar would be 10~12 m.The coal width designed would be two times wider than the width of the plastic zone and the theoretical calculation and the measured results could be well fitted.The site monitoring and measuring results showed that during the gateway driving period of the coal mining face,the gateway roof displacement at the coal pillar would be 85 mm,the convergence between the two side walls would be 70 mm and the separation in the shallow section of the roof would be 8 mm and 10 mm individually.During the mining operation period,convergence of the roof and the two side walls was increased to 105 mm and 90 mm individually,the separation in the roof strata was not changed

  6. SEEPAGE FIELD-STRAIN FIELD COUPLING ANALYSIS FOR ROCK MASSES OF COAL SEAM FLOOR DURING MINING ABOVE A CONFINED AQUIFER%煤层底板岩体采动渗流场-应变场耦合分析

    Institute of Scientific and Technical Information of China (English)

    姚多喜; 鲁海峰

    2012-01-01

    根据五沟煤矿1018 工作面地质及水文地质条件,应用三维快速拉格朗日(FLAC3D)流固耦合分析模块,采用变渗透系数方法,对该工作面底板岩体采动渗流应变机制进行数值模拟研究.分析结果表明:采动影响下,围岩渗透系数发生较大的变化,处在采空区正上方的泥岩段最大达到原始渗透系数的1293倍;根据渗流场分析,工作面采动并没有破坏底板隔水层的阻水性能,采动裂隙没有导通灰岩含水层,灰岩水涌入回采工作面形成水害可能性较小;工作面正下方岩体单元安全度小于1的区域最大深度为30 m.综合渗流场以及隔水底板单元安全度分析结果,10煤底板下灰岩水溃入工作面形成水害可能性较小.%Based on the geological and hydrogeological conditions of the face 1018 in Wugou coal mine, the fluid-solid coupling module in FLAC3D with changeable permeability coefficient is adopted to simulate the whole process of damage and failure of rock masses at floor of the coal seam No. 10. The results indicate that the permeability coefficient of surrounding rocks changes a lot due to mining. The maximum permeability coefficient reaches 1 293 times of the original one, which happens at the immediate roof of mined-out area. According to the analysis of seepage field, mining does not destroy water resistance of floor aquifer. Mining fissures do not connect limestone aquifers, and water in the limestone is less likely to flow into stopes to cause damage. The maximum depth of rock masses with element safety degree less than one is about 30 m. According to the change of permeability coefficient of and the analytical results of element safety degree of rock masses, safe mining of the face 1018 can be ensured.

  7. 煤矿3煤层底板水害预测研究%Study on the Prediction of Floor Flood for the 3 Coal Seam of a Coal Mine

    Institute of Scientific and Technical Information of China (English)

    张有为; 肖标丁

    2016-01-01

    China is one of the countries that have serious flood disaster. In the process of safe production of many coal mines, the water inrush of coal floor is a common problem. Coal mine A faces with the coal mining safety problem of floor water inrush. In this paper, combining with the geological environment of coal mine A, the main flood and water inrush examples are described in detail. The water inrush coefficient method is used to predict the risk of water inrush in a coal mine. The research results have important theoretical and practical significance for preventing and controlling the water inrush and realizing the safe production of the coal mine.%我国是受水害较严重的国家之一,很多煤矿在安全生产过程中,煤层底板突水是比较常见的问题,煤矿A就面临着底板突水的采煤安全问题。本文结合煤矿A地质环境,详细介绍了矿井主要水害及突水实例,再运用突水系数法对某煤矿进行突水危险性预测。研究结果对防治煤层底板突水和实现煤矿安全生产具有重要的理论意义和实际意义。

  8. Comparative Studies on the Combustion Kinetics of Chars Prepared from Brown and Bituminous Coals under Air (O_2/N_2) and Oxy-fuel (O_2/CO_2) Conditions

    OpenAIRE

    Kim, Hyun-Seok; Wada, Nozomi; Nozawa, Sohey; Matsushita, Yohsuke; Yamamoto, Tsuyoshi; Oomori, Motohira; Harada, Tatsuro; Miyawaki, Jin; Yoon, Seong-Ho; Mochida, Isao

    2012-01-01

    This paper deals with the application of a solid-gas reaction model which can describe the combustion and gasification mechanism for air (O_2/N_2) and oxy-fuel (O_2/CO_2) conditions. Loy Yang brown coal was used as a sample after pyrolysis, together with Newlands coal as bituminous coal for comparison of coal ranks. By carrying out the thermogravimetric analysis (TGA) run under non-isothermal conditions, chemical reaction rates of partial oxidation reaction and gasification reaction were esti...

  9. Development of scientific and technological bases for application of brown coal semi coke in the technology of non- milled silicon carbide

    Science.gov (United States)

    Anikin, A. E.; Galevsky, G. V.; Rudneva, V. V.; Nozdrin, E. V.; Galevsky, S. G.

    2016-09-01

    Thermodynamics is investigated, and the optimum temperature and time modes of carbonization of a briquetted silica fume batch- brown coal semi coke are defined. The complete carbonization of the batch in the conditions of heat treatment is achieved at a temperature of 1923 - 1973 K within 15 - 20 minutes. The conditions and indicators of the chemical enrichment of carbonization products are established. After enrichment, the carbide content is more than 90%. Silicon carbide micro-powder is obtained with a specific surface area 8000 - 9000 m2/kg.

  10. 云南省威信县新庄煤矿区C5煤层瓦斯地质规律研究%Study on Xinzhuang Coalmine Area Coal Seam C5 Gas Geological Hosting Pattern in Weixin County, Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    庞君; 李宗祥; 朱绍兵; 王巨民; 张帅

    2012-01-01

    云南威信县新庄煤矿区多为高瓦斯及煤与瓦斯突出矿井,该矿区总体上为一向斜,发育一系列轴向NEE的次级褶曲,瓦斯含量为0.25~40.55m3/t,平均为9.10m3/t.通过对矿区地质构造、煤层厚度、煤的变质程度、顶板岩性、煤层埋深、水文地质条件等瓦斯地质因素分析,其瓦斯分布规律总体上受向斜控制,瓦斯含量在次级构造(如向斜轴部)较高,瓦斯含量等值线总体上呈NEE向展布,瓦斯含量与煤层厚度呈正相关,瓦斯含量在浅部煤层中变化大,随埋深增大趋于增高,在600m以深,瓦斯含量增加的速度减慢;从泥岩顶板-泥质灰岩顶板-粉砂岩顶板,煤层瓦斯含量依次显著降低;矿区浅部地下水活动较活跃,随深度增加,下水头压力增大,有利于瓦斯的保存和富集,区内岩溶发育但大部分位于地表,对C5煤层影响甚微.%Coalmines in the Xinzhuang coalmine area are mostly high gas and coal-and-gas out-burst mines, the coalmine area is a syncline in general, developed a series of NEE axial secondary folds, with gas content 0.25 ~40.55m3/t, average 9.10m3/t. Through analyses of mine area gas geological factors including geological structure, coal seam thickness, degree of coal metamorphism, roof lithology, coal seam buried depth, hydrogeological condition have demonstrated that the gas distribution pattern is controlled by the syncline in the mass. Gas content is rather high in secondary structures (such as in syncline axis), gas content contour lines NEE distributed as a whole. Gas content presents positively correlated with coal seam thickness; gas content is variable in shallow part coal seams, increasing along with the increasing of buried depth, acceleration decreasing below the depth of 600m. Gas content obvious decrease successively from in mudstone roof-argillaceous limestone roof-siltstone roof. Groundwater is relatively active in coalmine area shallow part, along with the increasing depth

  11. Automated methods and control when mining seams prone to outburst

    Energy Technology Data Exchange (ETDEWEB)

    Kolesov, O.A.; Agaphonov, A.V.; Kolchin, G.I. [Makeyevka Safety in Mines Research Institute (Ukraine)

    1995-12-31

    Drawbacks in existing methods of predicting outburst zones in Donbas (Russia) thin coal seams led specialists at MakNII to investigate methods based on artificial excited acoustic signals, with processing by personnal computers. The paper describes investigations to correlate different acoustic signal parameters with stress and strained state of the massif preface. The method proved reliable in determining the relief zone in 12 Donbas mines. The paper goes on to describe development of a control method for another widely used method of coal and gas outburst prevention in Donbas, that of water injection into the coal seam known as `hydroripping`. This method includes acoustic signals recording and preface part parameters determination in the drilling process for infusion and recording and processing of the acoustic signal in real time, which is created during water infusion. 8 refs.

  12. Modeling of pulverized coal combustion processes in a vortex furnace of improved design. Part 2: Combustion of brown coal from the Kansk-Achinsk Basin in a vortex furnace

    Science.gov (United States)

    Krasinsky, D. V.; Salomatov, V. V.; Anufriev, I. S.; Sharypov, O. V.; Shadrin, E. Yu.; Anikin, Yu. A.

    2015-03-01

    This paper continues with the description of study results for an improved-design steam boiler vortex furnace, for the full-scale configuration of which the numerical modeling of a three-dimensional turbulent two-phase reacting flow has been performed with allowance for all the principal heat and mass transfer processes in the torch combustion of pulverized Berezovsk brown coal from the Kansk-Achinsk Basin. The detailed distributions of velocity, temperature, concentration, and heat flux fields in different cross sections of the improved vortex furnace have been obtained. The principal thermoengineering and environmental characteristics of this furnace are given.

  13. Improving methods of extracting thick seams in the Kuzbass. Sovershenstvovanie sposobov razrabotki moshchnykh plastov v Kuzbasse

    Energy Technology Data Exchange (ETDEWEB)

    Tomashevskii, L.P.

    1985-01-01

    This report reviews mining conditions in the Prokop'evsk-Kiselevsk coal fields characterized by tectonic faults, well developed foldings, convergence of seams and propensity to spontaneous ignition. Discusses trends in the development of new and the improvement of old extraction methods (mining machines KPK, AK3 for 35-65 degree inclined seams up to 10 m thick, KNK, 20 KP-70 for seams over 10 m thick and KGS3, KV3 for extraction with stowing). Analyzes improved mining machines for use with flexible canopies (KMS cutter-loaders incorporating powered supports used for extracting 5 m thick 35-75 degree inclined seams); complex type 2ANShch for extraction of coal and erection of flexible canopies. Discusses method of extracting coal under flexible canopies by long diagonal faces with cutting advanced kerfs; mining thick seams and fold ridges by horizontal slicing employing FRG and Soviet props ('Tolstyi' seam, 35 m thick inclined 32-43 degrees and 45 m longwalls cutting 3 m slices); air supplies through diagonal boreholes. Describes trials of new double and diagonal canopies; extraction of faulted seams by horizontal layers with caving. Detailed discussion of the dynamics of pillar fragmentation and methods of erecting interhorizontal isolation strips to prevent spontaneous fires using consolidated rock and solidifying stowing.

  14. 3D Coal Seam Modeling Based on Pseudo Point Elimination and Four Fields Spline Interpolation%基于伪点剔除与四域样条插值的三维煤层建模

    Institute of Scientific and Technical Information of China (English)

    肖静

    2014-01-01

    In accurate modeling of three-dimensional, the result was affected by the underground coal faults, rock, undulat⁃ing terrain and other factors, so the modeling accuracy was not high. To improve the accuracy of three-dimensional model⁃ing of coal, an algorithm of three-dimensional coal seam modeling with pseudo point elimination and four fields spline inter⁃polation was proposed, the pseudo point was pretreated, and the isolated point was removed, the remaining non-isolated point was used for establishing the basic model and rebuilding the model, the spline interpolation method was used for the four domains of non-isolated point modeling, modeling, the modeling domain was divided into the starting field, extending the domain, stable domain and the convergence domain, in different domains, different modeling point of matching weight⁃ed interpolation was processed, filtering through four domains were combined to achieve the four domains spline interpola⁃tion, it played a role of smoothing filter in modeling, thus the accuracy of three-dimensional modeling was greatly im⁃proved. Simulation results show that the new algorithm has good robustness for external faults, rock, undulating terrain, the 3D modeling accuracy was improved and the computation is less.%三维煤层精确建模受地下断层、岩层、地势起伏等因素的影响,建模精度不高。为提高三维煤层建模的精度,提出一种基于伪点剔除与四域样条插值的三维煤层精确建模算法,通过伪点剔除方法对建模点进行预处理,筛选出其中的孤立点,进行剔除,其余非孤立点用于基本模型建立和基于映射的模型重构,采用四域样条插值方法对非孤立点进行建模,在建模中,将建模域分为起始域、延伸域、稳定域、收敛域共四个域,在不同域中,对不同的建模点进行匹配加权插值处理,经过四域联合滤波,实现四域样条插值,对建模效果起到平滑

  15. Watermanagement - related and ecological demands on brown-coal mining. A statement of position; Wasserwirtschaftlich-oekologische Forderungen fuer den Braunkohlenabbau. Positionspapier

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-01-01

    This statement of position aims to identify influences exerted before, during and after brown-coal open-pit mining activities and to assess them in general terms from a water-management and ecological viewpoint. The form chosen is that of individual, concise postulates. Each of these is followed by an explanation. To illustrate the great variety of potentially arising problems, the major German brown-coal mining districts Lausitz, eastern Germany, and Lower Rhine are dealt with. A particular characteristic of the eastern German and Lausitz mining districts is that as the demand structure abruptly collapsed early in the 90s, closures became necessary on a large scale without preparatory measures having been taken. (orig.) [Deutsch] Mit dem vorliegenden Positionspapier wurde der Versuch unternommen, die Beeinflussungen vor, waehrend und nach dem Abbau von Braunkohle im Tagebaubetrieb inhaltlich zu erfassen und aus wasserwirtschaftlich-oekologischer Sicht verallgemeinernd zu bewerten. Dabei ist die From einzelner kurzgefasster Forderungen gewaehlt worden. Jede dieser Forderungen ist durch eine Erlaeuterung untersetzt. Um die Vielfalt der auftretenden Probleme zu verdeutlichen, werden beispielhaft in einem Anhang die grossen deutschen Braunkohlenreviere in der Lausitz, in Mitteldeutschland und am Niederrhein vorgestellt. Fuer das Mitteldeutsche und das Lausitzer Revier ist besonders anzumerken, dass mit dem schlagartigen Zusammenbruch der Bedarfsstruktur am Anfang der 90er Jahre in grossem Umfang Stillegungen ohne entsprechende Vorarbeiten notwendig wurden. (orig.)

  16. Experiments for the development of a circulating pressurized gasification plant (brown coal feeding and combustion). Combustion exeriments. Coal feeding experiments. Final report; Verfahrenstechnische Versuche fuer die Entwicklung einer zirkulierenden Druckwirbelschichtfeuerung (Braunkohleeintrag und -verbrennung). Verbrennungsversuche. Kohleeintragsversuche. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-09-01

    Combustion experiments with moist raw LAUBAG and MIBRAG coal were carried out in the pressurized gasification pilot plant at Friedrichsfeld. The following parameters wre investigated: Ignition and combustion behvaviour of the moist brown coal in a pressurized gasification plant; Emission ratings of CO, N{sub 2}O, NO{sub x}, SO{sub 2} and dust contents of standard coal; Combustion efficiencies at furnace temperatures over 850 C as determined by ash analysis; Measurements of the temperature distribution in the fluidized bed; Brown coal fly ash retention capacity of the hot gas filters; Analysis of ash turnover in order to maintain a stable circulation; Investigation of ash abrasion in circulating operation; Performance tests of secondary systems, e.g. feeding systems, ash removal systems for fly ash and bed ash, and measurement of the thermodynamic data in the ash cooler. [Deutsch] In der Druckwirbelschicht-Versuchsanlage Friedrichsfeld sind Verbrennungsversuche mit rohfeuchter LAUBAG- und rohfeuchter MIBRAG-Kohle durchgefuehrt worden. Bei genereller Verwendung des Aufbaus der Versuchsanlage Friedrichsfeld waren folgende Betriebs-/Auslegungswerte zu ermitteln: Ermittlung des Zuend- und des Ausbrandverhaltens der feuchten Braunkohle in der zirkulierenden Druckwirbelschichtfeuerung; Bestimmung der Emissionswerte wie CO, N{sub 2}O, NO{sub x}, SO{sub 2} und Staubgehalt fuer die Auslegungskohle; Bestimmung der Ausbrandwerte in der Asche bei einer Feuerraumtemperatur von ueber 850 C; Messung der Temepraturverteilung in der Wirbelschicht; Verhalten der Heissgasfilter bei Beaufschlagung mit Braunkohleflugasche; Untersuchung des Aschehaushaltes zur Erhaltung eines stabilen Zirkulationsbetriebes; Untersuchung des Ascheabriebverhaltens im Zirkulationsbetrieb; Pruefung der Funktionstuechtigkeit von Nebenanlagen wie Bekohlungseinrichtungen, Entaschungseinrichtungen fuer Flug- und Bettasche sowie Ermittlung der thermodynamischen Daten im vorhandenen Aschekuehler. (orig./HS)

  17. 厚松散层煤层开采岩层移动与破坏规律试验研究%A Test Research on the Law of Rock Movement and Damage in Mining of Coal Seams of Thick Loess

    Institute of Scientific and Technical Information of China (English)

    王少华; 刘凡; 朱兴军; 许善文

    2013-01-01

    Underground coal mining is simulated by using similar material simulation experiment and the observation point set up on the model. The paper summarizes the "three zones" development under the condition of thick coal seam mining and general rule of strata movement and destruction.%利用相似材料模拟试验模拟井下煤层开采,通过在模型上设置测量观测点,采用全站仪测量的方法对观测点进行定期观测,通过对试验观测数据和显现特征分析,总结了厚松散层条件下煤层开采过程中“三带”的发育情况和岩层移动与破坏的一般规律.

  18. Basic phenomena and methods for forecasting floor heave in coal seams in the Donbass on the basis of geologic prospecting and mining. Osnovnye faktory proyavleniya i metody prognozirovaniya pucheniya porod pochvy ugol'nykh plastov Donbassa po dannym geologorazvedochnykh i gornykh rabot

    Energy Technology Data Exchange (ETDEWEB)

    Kucherenko, M.T.; Sokol' skaya, Kh.V.; Shestakov, G.P. (DO Institut Mineral' nykh Resursov (USSR))

    1988-01-01

    Evaluates factors that influence floor heave in mine roadways of the Donbass. The following factors are analyzed: coal dip angle, mining depth, lithology of rock strata in the floor, content of clay particles, stratification (layers of clay, aleurites and sandstones), thickness of rock layers prone to swelling, coal seam thickness, mineral content and stratification of surrounding strata, sulfur content in coal, moisture content in coal and rock strata, water influx rates, chemical composition of mine water, dimensions of a mine roadway, roof type (stable, unstable, relatively stable, easy to break down, difficult to break down), roadway position in relation to working faces in overlying or underlying strata, face advance rate and face dimensions, types of strata control in mine roadways (coal pillars left along a mine roadway, roadside packs etc.), equipment used for strata control at working faces as well as mining equipment. Methods for forecasting floor heave considering the main factors that influence rock swelling are comparatively evaluated. Recommendations for floor heave control are made. 22 refs.

  19. Study on strength matching of prismatic drilling rod when drilling soft and outburst coal seam%棱状钻杆应用于松软突出煤层钻进强度匹配研究

    Institute of Scientific and Technical Information of China (English)

    王永龙; 孙玉宁; 翟新献; 宋维宾; 王振锋

    2014-01-01

    To solve the problem in strength matching of prismatic drilling rod , the mechanical analysis model of dif-ferent prismatic drilling rods were established by the physical design and numerical analysis software , and its strength and edges structure were analyzed .The results showed that the strength matching of conventional prismatic drilling rod is unreasonable .The thread of drilling rod exists the problems of vulnerabilities , lower safety factor and unbalance distribution .The technical means , such as increasing the diameter of the joint , optimizing joint and edge structure , and applying friction welding technology etc ., were adopted to improve the overall strength of the pris-matic drilling rod.The overall safety factor of improved prismatic drilling rod had more balanced distribution and less undulation , and the overall mechanical properties of the drilling rod were effectively improved .By engineering application , the problems of drilling rod dropping and breaking frequently when drilling in complex conditions coal seam were solved .The average depth of borehole exceeded the design depth , and the drilling efficiency improved by 20%, without the accidents of drilling rod dropping and breaking during the test .%为解决棱状钻具的强度匹配问题,应用实体设计和数值分析软件,建立不同结构棱状钻具力学分析模型,对其进行强度分析,优化棱状钻具结构。分析结果表明,常规棱状类钻具整体强度匹配不合理,丝扣位置存在受力薄弱点,安全系数较低且整体分布不均衡。可采取加大接头直径、优化接头及棱边结构、应用摩擦焊接工艺等技术手段提高棱状钻具整体强度;改进后的棱状钻杆,整体安全系数分布均衡、波动小,钻杆整体力学性能得到了有效的提高。通过工程应用,解决了煤矿复杂条件煤层钻孔施工丢钻、断钻频繁的被动局面,平均深度超过了设

  20. Study on Strata Pressure Behavior Features of Fully-Mechanized Top Coal Mining in Soft Large Inclined Angle Seam%大倾角松软煤层综放开采矿压显现规律研究

    Institute of Scientific and Technical Information of China (English)

    朱现磊; 杨仁树; 蔡志炯; 祁海军

    2014-01-01

    为了探讨大倾角松软煤层综放开采顶板活动规律,运用物理相似模拟试验与现场实测相结合的方法,研究了覆岩运移特征、顶板垮落步距及矿压显现规律。结果表明:覆岩下沉曲线呈非对称性,最大下沉量随高度增加而减小;工作面上段矿压显现强于中段,下段最弱,且两端头来压时间滞后于中部来压;工作面巷道支承压力最大值位于超前工作面17~25 m,超前工作面约40 m范围内应重点加强支护。试验结果与现场观测基本相符,为工作面支架选型提供了依据。%In order to study the roof movement features of fully-mechanized top coal mining in soft large inclined angle seams,the overlaying strata displacement,roof weighting step and mining pressure appearance were researched by using analogy simulation tests and the field monitoring.The results showed that overlaying strata sinked asymmetry and maximum subsidence decreased with increasing height in the process of mining face.The greatest strength and biggest weakness of mining pressure appearance were upper and lower part,taking on faster in the middle than in the ends.The maximum abutment pressure was in 17~25 m ahead the working face,the support strength should be strengthened within 40 m ahead the working face.The test results and field observation were in substantial agreement,which could provide the guidance references to the hydraulic powered support selection.

  1. Based on the optimization of deep-hole rend blasting technology in low-permeability coal seam analysis%基于低渗透煤层深孔预裂爆破工艺优化的考察分析

    Institute of Scientific and Technical Information of China (English)

    王玉杰; 仝艳军; 杨继东

    2015-01-01

    Against a single low permeability outburst coal seam deep hole presplit blasting charge difficult, technical problems of sealing, guided by the theory of deep-hole pre-splitting blasting. a further optimisation of the construction process, guiding the construction. Practice shows, using new technology for deep-hole presplitting blasting destressing, can effectively solve the outburst coal seam deep hole presplit blasting charge difficult, difficult technical problems such as sealed, greatly improve working efficiency, provide technical support for mine safety production.%针对单一低渗透突出煤层深孔预裂爆破存在的装药难、封孔难的技术问题,以深孔预裂爆破理论为指导,进一步优化了施工工艺,指导现场施工。现场应用表明,利用深孔预裂爆破卸压增透新工艺,可有效解决突出煤层深孔预裂爆破存在的装药难、封孔难等技术难题,大幅度提高工作效率,为突出矿井安全生产提供技术支撑。

  2. Developing selective mining capability for longwall shearers using thermal infrared-based seam tracking

    Institute of Scientific and Technical Information of China (English)

    Jonathon C. Ralston; Andrew D.Strange

    2013-01-01

    Longwall mining continues to remain the most efficient method for underground coal recovery.A key aspect in achieving safe and productive longwall mining is to ensure that the shearer is always correctly positioned within the coal seam.At present,this machine positioning task is the role of longwall personnel who must simultaneously monitor the longwall coal face and the shearer's cutting drum position to infer the geological trends of the coal seam.This is a labour intensive task which has negative impacts on the consistency and quality of coal production.As a solution to this problem,this paper presents a sensing method to automatically track geological coal seam features on the longwall face,known as marker bands,using thermal infrared imaging.These non-visible marker bands are geological features that link strongly to the horizontal trends present in layered coal seams.Tracking these line-like features allows the generation of a vertical datum that can be used to maintain the shearer in a position for optimal coal extraction.Details on the theory of thermal infrared imaging are given,as well as practical aspects associated with machine-based implementation underground.The feature detection and tracking tasks are given with real measurements to demonstrate the efficacy of the approach.The outcome is important as it represents a new selective mining capability to help address a long-standing limitation in longwall mining operations.

  3. Technological properties of coal from the Kusheyakovskii deposit in the Kuzbass

    Energy Technology Data Exchange (ETDEWEB)

    Proskuryakov, A.E.; Ivanov, V.P.; Stankevich, A.S.; Podchishchaeva, N.I.; Chegodaeva, N.A.

    1986-11-01

    The Kusheyakovskii black coal deposit in the southeastern Kuzbass consists of 25 seams 1.0-2.5 m thick with dip angles to 20 degrees. Black coal from the deposit is characterized by relatively high vitrinite content from 70 to 82% and low exinite content from 1 to 3%. Coal rank described by vitrinite reflectivity ranges from 0.66 to 0.86%, volatile matter from 39.7% to 35.9%. Coal from the 5-7 seam group is classified as G6 power coal. Coal from the 10-11 seam group is also classified as G6 power coal but its caking power is greater. The 12-13 seam group is most valuable as about half of the coal seams consists of caking gas or gas-lean coal. Coal characteristics are given in 3 tables.

  4. Failure probability analysis of coal crushing induced by uncertainty of influential parameters under condition of in-situ reservoir

    Institute of Scientific and Technical Information of China (English)

    张立松; 闫相祯; 杨秀娟; 田中兰; 杨恒林

    2014-01-01

    The uncertainties of some key influence factors on coal crushing, such as rock strength, pore pressure and magnitude and orientation of three principal stresses, can lead to the uncertainty of coal crushing and make it very difficult to predict coal crushing under the condition of in-situ reservoir. To account for the uncertainty involved in coal crushing, a deterministic prediction model of coal crushing under the condition of in-situ reservoir was established based on Hoek-Brown criterion. Through this model, key influence factors on coal crushing were selected as random variables and the corresponding probability density functions were determined by combining experiment data and Latin Hypercube method. Then, to analyze the uncertainty of coal crushing, the first- order second-moment method and the presented model were combined to address the failure probability involved in coal crushing analysis. Using the presented method, the failure probabilities of coal crushing were analyzed for WS5-5 well in Ningwu basin, China, and the relations between failure probability and the influence factors were furthermore discussed. The results show that the failure probabilities of WS5-5 CBM well vary from 0.6 to 1.0; moreover, for the coal seam section at depth of 784.3-785 m, the failure probabilities are equal to 1, which fit well with experiment results; the failure probability of coal crushing presents nonlinear growth relationships with the increase of principal stress difference and the decrease of uniaxial compressive strength.

  5. Numerical simulation and imaging of scattered wave of sunk pillar in coal seam%煤层陷落柱散射波数值模拟与成像

    Institute of Scientific and Technical Information of China (English)

    曹志勇; 王伟; 王赟

    2012-01-01

    The scattered wave theory has built the basis of scattered wave imaging of the sunken pillar in coal field seismic exploration. When seismic waves meet with the scatter point underground, the waves propagate around and generate scattered waves. And then reflection is formed by enhancing energy interference of scattered waves. Through the numerical modeling, we can receive the scattered waves from the steep dip interface of the sunken pillar in coal seam. After researching wave characteristic on common scatter point (CSP) gathers, we can recognize the scattered waves, and obtain the information of geologic structure underground, including the structure position and the outline of heterogeneous geologic body. Tested with field seismic data, the result of scattered wave imaging indicates that the equivalent offset method (EOM) can reasonably and accurately use the information of scattered waves, and the pre-stack time migration based on EOM is an effective method for the imaging of sunken pillars and inhomogeneous geologic bodies.%煤层陷落柱是煤田勘探开发中常见的一种典型的非均匀地质体.由于来自陷落柱的反射信号少、反射能量弱,使得基于反射波原理的常规地震成像方法难以有效识别陷落柱.本文以散射波理论为基础,采用数值模拟方法,研究了陷落柱的散射波场特征,研究表明地面接收的波场中含有来自陷落柱陡倾角界面的散射波场.通过共散射点道集波场的模拟,可以清晰地识别散射波,获得地下散射点和非均匀地质体的信息,判断散射点的位置,从而勾画出不均匀地质体的形态.采用等效偏移距假设抽取共散射点道集,在此基础上进行叠前偏移,对陷落柱成像;模拟与实际数据成像结果对比表明此方法能够合理地提取散射点的散射波场信息,对陷落柱形态及内部结构准确成像,是一种有效的煤田陷落柱成像方法.

  6. 松软突出煤层水平钻孔反循环气力排屑机理%Chip removal mechanism by air reverse circulation during horizontal drilling in soft outburst coal seam

    Institute of Scientific and Technical Information of China (English)

    韩晓明; 张龙列; 刘瑜; 铁占续

    2015-01-01

    In order to solve the problem of difficult hole-making in gas drainage during bedding drilling process , a new technology of chip removal by air reverse circulation through the drill rod bore during the gas drainage drilling in soft outburst coal seam was put forward .The mathematical model of air reverse circulation conveying on coal cut-tings particles in rod bore was established , and the variation laws of conveying pressure loss and solid phase velocity were analyzed by simulation .The results showed that under the effect of air reverse circulation in the process of bedding horizontal drilling , the air velocity in the upper part of drill rod bore is relatively stable , while in the under part of drill rod bore , the air velocity close to the wall decreases significantly and is less than that in the central zone .In the same location the air velocity becomes greater with the increase of conveying concentration .Under dif-ferent conveying concentration , the pressure loss in the drill rod bore reduces and then increases with the increase of conveying air velocity .There exists a best economic speed in chip removal by air reverse circulation through the drill rod bore .%为了解决顺层钻进瓦斯抽放钻孔成孔难的问题,提出了松软突出煤层瓦斯抽放钻孔钻杆内孔反循环气力排屑新技术,建立煤屑颗粒在钻杆内孔的反循环气力输送数学模型,经仿真求解,分析了输送压力损失及固相速度的变化规律。结果表明,在顺层水平钻孔钻进过程中,煤屑在反循环气力作用下,气流速度在钻杆内孔中上部比较稳定,而在钻杆内孔下部靠近内壁处的气流速度明显下降且小于中心区域;在同一位置输送浓度越大,气流速度也越大;在输送浓度不同的情况下,随着输送气流速度的增加,钻杆内孔的压力损失先降低再增高,在钻杆内孔反循环气力排屑时存在最佳经济速度。

  7. Unique Project of Single-Cutting Head Longwall Shearer Used for Thin Coal Seams Exploitation / Projekt Jednoorganowego Kombajnu ŚCIANOWEGO O Specjalnej Konstrukcji Przeznaczonego do Eksploatacji POKŁADÓW Cienkich

    Science.gov (United States)

    Bołoz, Łukasz

    2013-12-01

    Problem of thin hard coal seams exploitation, including chosen data related with their resources in Poland, has been discussed in the introduction of the present study. On the basis of actually operated machines the assumptions, which should be satisfied by the longwall shearer used for exploitation of thin hard coal seams, have been made. A project of such longwall shearer combined with band conveyor and mechanized longwall support, including description of the machine operation technology and analysis of possible day output achievement, have been presented. Polska dysponuje stosunkowo dużymi zasobami surowców energetycznych, a ciągle rosnące zapotrzebowanie na energię skłania do ich racjonalnego wykorzystywania. Jedną z możliwości takiego racjonalnego gospodarowania zasobami naturalnymi jest eksploatacja węgla kamiennego z pokładów cienkich. W związku z wybieraniem coraz cieńszych pokładów węgla, zalegających bardzo głęboko, w trudnych warunkach górniczo-geologicznych napotyka się na duże problemy związane z uzyskaniem wymaganej wydajności wydobycia przy użyciu stosowanych aktualnie metod. Przyjmuje się, ze pokłady cienkie to takie o miąższości od 1.0 m do 1.5 m i właśnie ta niewielka wysokość wyrobiska ścianowego powoduje szereg ograniczeń związanych z efektywną eksploatacją węgla. Na podstawie dostępnych danych określono, że ilości węgla kamiennego w cienkich pokładach wynosi około 600 mln Mg. Znaczna część pokładów cienkich w ostatnich latach została przeklasyfikowana na nieprzemysłowe, co pozwala stwierdzić, że rzeczywista ilość węgla w pokładach cienkich jest znacznie większa. Na podstawie analizy wad i zalet jak i danych technicznych produkowanych obecnie maszyn, określono wytyczne i założenia do nowego rozwiązania maszyny urabiającej przeznaczonej do wydobywania węgla w ścianach niskich. Kombajn do eksploatacji cienkich pokładów powinien spełniać następujące wymagania (Bołoz, 2012

  8. A Poromechanical Model for Coal Seams Injected with Carbon Dioxide: From an Isotherm of Adsorption to a Swelling of the Reservoir Un modéle poromécanique pour l’injection de dioxyde de carbone dans des veines de charbon : d’une isotherme d’adsorption à un gonflement du réservoir

    Directory of Open Access Journals (Sweden)

    Nikoosokhan S.

    2012-11-01

    Full Text Available Injecting carbon dioxide into deep unminable coal seams can enhance the amount of methane recovered from the seam. This process is known as CO2-Enhanced Coal Bed Methane production (CO2-ECBM. The seam is a porous medium whose porous system is made of cleats (small natural fractures and of coal pores (whose radius can be as small as a few angström. During the injection process, the molecules of CO2 get adsorbed in the coal pores. Such an adsorption makes the coal swell, which, in the confined conditions that prevail underground, induces a closure of the cleat system of the coal bed reservoir and a loss of injectivity. In this work, we develop a poromechanical model which, starting from the knowledge of an adsorption isotherm and combined with reservoir simulations, enables to estimate the variations of injectivity of the coal bed reservoir over time during the process of injection. The model for the coal bed reservoir is based on poromechanical equations that explicitly take into account the effect of adsorption on the mechanical behavior of a microporous medium. We consider the coal bed reservoir as a dual porosity (cleats and coal porosity medium, for which we derive a set of linear constitutive equations. The model requires as an input the adsorption isotherm on coal of the fluid considered. Reversely, the model provides a way to upscale an adsorption isotherm into a meaningful swelling of the coal bed reservoir at the macroscopic scale. The parameters of the model are calibrated on data on coal samples available in the literature. Reservoir simulations of an injection of carbon dioxide in a coal seam are performed with an in-house finite volume and element code. The variations of injection rate over time during the process of injection are obtained from the simulations. The effect of the compressibility of the coal matrix on those variations is discussed. L’injection de dioxyde de carbone dans des veines de charbon profondes peut augmenter

  9. Micro-CT experimental of the thermal cracking of brown coal%褐煤热破裂的显微CT实验

    Institute of Scientific and Technical Information of China (English)

    孟巧荣; 赵阳升; 胡耀青; 冯增朝; 徐素国

    2011-01-01

    Using μCT225kVFCB high precision micro-CT system and a small moveable argon furnace, thermal cracking of brown coal from Pingzhuang mining in Inner Mongolia municipality was studied under different temperature.The results show that for brown coal,the big cracks( >800 μm) occupy leading position at about 100 ℃ ,the medium cracks ( 100 ~ 400 μm) are more important than others at about 200 ℃, the micro-cracks ( < 100 μm)become dominant above 300 ℃ ;threshold temperature of thermal cracking is 300 ℃, more or less;when temperature is lower than 300 ℃, the formation and evolution of crack and pore result mostly from thermal cracking, above 300 ℃, micro-cracks and pores produce mainly because coal pyrolysis produce and release oil gas, and turn coal skeleton into char gradually with temperature.%采用μCT25kVFCB型高精度显微CT试验系统并配以微型气氛炉,研究了内蒙古平庄褐煤热破裂随温度的变化关系.研究结果表明,褐煤在l00℃左右时,大裂隙(>800μm)占主导地位;200℃左右时,中等裂隙(100~400μm)占主导地位;300℃之后微裂隙(<100μm)占主导地位;热破裂的阈值为300℃左右;在300℃之前孔隙裂隙的产生发展主要是因为热破裂,300℃之后,微裂隙和孔隙的产生主要是因为煤体发生热解化学反应,油气逸出,固体骨架逐渐转变为半焦体.

  10. Safety Research on Determination of Support Working Resistance of Top Coal Caving in Extra Thick Coal Seam%煤矿矿井通风系统安全性绩效评价研究

    Institute of Scientific and Technical Information of China (English)

    周祺盛

    2015-01-01

    Strengthen the ventilation safety management, construct scientific, reasonable ventilation system, gas, coal dust and fire prevention of the accident fundamental measures, but also greatly reduce or even avoid the coal mine accident occurred in the most effective way. Ventilation safety performance evaluation is based on the essence of mine ventilation safety as the foundation, established in the closed-loop controlled taken ventilation safety in a series of safety control strategy, measures and a complete set of activities are used to measure the mine ventilation safety management level and the status quo of measurable results.%强化通风安全管理,构建科学、合理的通风系统,是预防瓦斯、煤尘以及火灾事故发生的根本措施,也是大幅度减少甚至避免煤矿重特大事故发生最有效的方法。通风安全绩效评价是以矿井通风安全本质化为基础,在通风安全所采取的一系列安全控制战略、措施和活动方面建立的一套完整的、可控的、闭环的,用于衡量矿井通风安全管理水平和现状的可测量的结果。

  11. Study of distribution of electromagnetic radiation of coal or rock before drivage face

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.; Wang, En.; He, X.; Liu, Z.; Jin, S.; Jia, H. [China University of Mining and Technology, Xuzhou (China). School of Mining and Safety Engineering

    2007-03-15

    In order to study the electromagnetic radiation (EMR) signals at different depths in coal mine driving, working faces were experimentally tested with KBD5 EMR monitoring equipment. Based on the coupling rule of stress and electricity, the relativity of deformation and fracture process of coal or rock and intensity of EMR was analyzed theoretically. The results show that there is a good relation between EMR and the coal stress state, and there are various stress states and deformation and fracture states in coal seams of working faces. There are 4 typical EMR distribution types: that of coal seam exposed for a long time that of coal seam after taking coal and gas outburst prevention measures, that of coal seam newly exposed, and that of coal seam having structure. 14 refs., 7 figs.

  12. Volatilisation of alkali and alkaline earth metallic species during the gasification of a Victorian brown coal in CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Quyn, Dimple Mody; Li, Chun-Zhu [CRC for Clean Power from Lignite, Department of Chemical Engineering, PO Box 36, Monash University, Victoria 3800 (Australia); Hayashi, Jun-ichiro [Centre