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 the...

A Comprehensive Overview of CO2 Flow Behaviour in Deep Coal Seams

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Mandadige Samintha Anne Perera

2018-04-01

Full Text Available Although enhanced coal bed methane recovery (ECBM and CO2 sequestration are effective approaches for achieving lower and safer CO2 levels in the atmosphere, the effectiveness of CO2 storage is greatly influenced by the flow ability of the injected CO2 through the coal seam. A precious understanding of CO2 flow behaviour is necessary due to various complexities generated in coal seams upon CO2 injection. This paper aims to provide a comprehensive overview on the CO2 flow behaviour in deep coal seams, specifically addressing the permeability alterations associated with different in situ conditions. The low permeability nature of natural coal seams has a significant impact on the CO2 sequestration process. One of the major causative factors for this low permeability nature is the high effective stresses applying on them, which reduces the pore space available for fluid movement with giving negative impact on the flow capability. Further, deep coal seams are often water saturated where, the moisture behave as barriers for fluid movement and thus reduce the seam permeability. Although the high temperatures existing at deep seams cause thermal expansion in the coal matrix, reducing their permeability, extremely high temperatures may create thermal cracks, resulting permeability enhancements. Deep coal seams preferable for CO2 sequestration generally are high-rank coal, as they have been subjected to greater pressure and temperature variations over a long period of time, which confirm the low permeability nature of such seams. The resulting extremely low CO2 permeability nature creates serious issues in large-scale CO2 sequestration/ECBM projects, as critically high injection pressures are required to achieve sufficient CO2 injection into the coal seam. The situation becomes worse when CO2 is injected into such coal seams, because CO2 movement in the coal seam creates a significant influence on the natural permeability of the seams through CO2

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.

Temperature field distribution of coal seam in heat injection

OpenAIRE

Zhang Zhizhen; Peng Weihong; Shang Xiaoji; Wang Kun; Li Heng; Ma Wenming

2017-01-01

In this article, we present a natural boundary element method (NBEM) to solve the steady heat flow problem with heat sources in a coal seam. The boundary integral equation is derived to obtain the temperature filed distribution of the coal seam under the different injecting conditions.

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.

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.

Integration of vertical and in-seam horizontal well production analyses with stochastic geostatistical algorithms to estimate pre-mining methane drainage efficiency from coal seams: Blue Creek seam, Alabama.

Science.gov (United States)

Karacan, C Özgen

2013-07-30

Coal seam degasification and its efficiency are directly related to the safety of coal mining. Degasification activities in the Black Warrior basin started in the early 1980s by using vertical boreholes. Although the Blue Creek seam, which is part of the Mary Lee coal group, has been the main seam of interest for coal mining, vertical wellbores have also been completed in the Pratt, Mary Lee, and Black Creek coal groups of the Upper Pottsville formation to degasify multiple seams. Currently, the Blue Creek seam is further degasified 2-3 years in advance of mining using in-seam horizontal boreholes to ensure safe mining. The studied location in this work is located between Tuscaloosa and Jefferson counties in Alabama and was degasified using 81 vertical boreholes, some of which are still active. When the current long mine expanded its operation into this area in 2009, horizontal boreholes were also drilled in advance of mining for further degasification of only the Blue Creek seam to ensure a safe and a productive operation. This paper presents an integrated study and a methodology to combine history matching results from vertical boreholes with production modeling of horizontal boreholes using geostatistical simulation to evaluate spatial effectiveness of in-seam boreholes in reducing gas-in-place (GIP). Results in this study showed that in-seam wells' boreholes had an estimated effective drainage area of 2050 acres with cumulative production of 604 MMscf methane during ~2 years of operation. With horizontal borehole production, GIP in the Blue Creek seam decreased from an average of 1.52 MMscf to 1.23 MMscf per acre. It was also shown that effective gas flow capacity, which was independently modeled using vertical borehole data, affected horizontal borehole production. GIP and effective gas flow capacity of coal seam gas were also used to predict remaining gas potential for the Blue Creek seam.

Non-mine technology of hydrocarbon resources production at complex development of gas and coal deposits

International Nuclear Information System (INIS)

Saginov, A.S.; Adilov, K.N.; Akhmetbekov, Sh.U.

1997-01-01

Non-mine technology of coal gas seams exploitation is new geological technological method of complex exploitation of coal gas deposits. The method allows sequentially to extract hydrocarbon resources in technological aggregative-mobile condensed states. According to natural methane content in seams the technology includes: methane extraction from sorption volume where it is bounded up with coal; gas output intensification of coal is due to structural changes of substance at the cost of physico-chemical treatment of seam; increase of seam permeability by the methods of active physical and physico-chemical actions on coal seam (hydro-uncovering, pneumatic hydro action etc.). Pilot testing shows efficiency of well mastering with help of depth pumps. In this case works of action of pumping out of operating liquid and gas extraction from coal seam are integrated

Gas Permeability Evolution Mechanism and Comprehensive Gas Drainage Technology for Thin Coal Seam Mining

Directory of Open Access Journals (Sweden)

Fangtian Wang

2017-09-01

Full Text Available A thin coal seam mined as a protective coal seam above a gas outburst coal seam plays a central role in decreasing the degree of stress placed on a protected seam, thus increasing gas permeability levels and desorption capacities to dramatically eliminate gas outburst risk for the protected seam. However, when multiple layers of coal seams are present, stress-relieved gas from adjacent coal seams can cause a gas explosion. Thus, the post-drainage of gas from fractured and de-stressed strata should be applied. Comprehensive studies of gas permeability evolution mechanisms and gas seepage rules of protected seams close to protective seams that occur during protective seam mining must be carried out. Based on the case of the LongWall (LW 23209 working face in the Hancheng coal mine, Shaanxi Province, this paper presents a seepage model developed through the FLAC3D software program (version 5.0, Itasca Consulting Group, Inc., Minneapolis, MI, USA from which gas flow characteristics can be reflected by changes in rock mass permeability. A method involving theoretical analysis and numerical simulation was used to analyze stress relief and gas permeability evolution mechanisms present during broken rock mass compaction in a goaf. This process occurs over a reasonable amount of extraction time and in appropriate locations for comprehensive gas extraction technologies. In using this comprehensive gas drainage technological tool, the safe and efficient co-extraction of thin coal seams and gas resources can be realized, thus creating a favorable environment for the safe mining of coal and gas outburst seams.

Depositional controls on coal distribution and quality in the Eocene Brunner Coal Measures, Buller Coalfield, South Island, New Zealand

Science.gov (United States)

Flores, R.M.; Sykes, R.

1996-01-01

The Buller Coalfield on the West Coast of the South Island, New Zealand, contains the Eocene Brunner Coal Measures. The coal measures unconformably overlie Paleozoic-Cretaceous basement rocks and are conformably overlain by, and laterally interfinger with, the Eocene marine Kaiata Formation. This study examines the lithofacies frameworks of the coal measures in order to interpret their depositional environments. The lower part of the coal measures is dominated by conglomeratic lithofacies that rest on a basal erosional surface and thicken in paleovalleys incised into an undulating peneplain surface. These lithofacies are overlain by sandstone, mudstone and organic-rich lithofacies of the upper part of the coal measures. The main coal seam of the organic-rich lithofacies is thick (10-20 m), extensive, locally split, and locally absent. This seam and associated coal seams in the Buller Coalfield are of low- to high-volatile bituminous rank (vitrinite reflectance between 0.65% and 1.75%). The main seam contains a variable percentage of ash and sulphur. These values are related to the thickening and areal distribution of the seam, which in turn, were controlled by the nature of clastic deposition and peat-forming mire systems, marine transgression and local tidal incursion. The conglomeratic lithofacies represent deposits of trunk and tributary braided streams that rapidly aggraded incised paleovalleys during sea-level stillstands. The main seam represents a deposit of raised mires that initially developed as topogenous mires on abandoned margins of inactive braidbelts. Peat accumulated in mires as a response to a rise in the water table, probably initially due to gradual sea-level rise and climate, and the resulting raised topography served as protection from floods. The upper part of the coal measures consists of sandstone lithofacies of flu vial origin and bioturbated sandstone, mudstone and organic-rich lithofacies, which represent deposits of paralic (deltaic

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

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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.

The relation between district raise in the multiple coal seams and its pillars

Energy Technology Data Exchange (ETDEWEB)

Zhai, X. [Jiaozuo Institute of Technology, Jiaozuo (China). Dept. of Mining Engineering

2002-02-01

Based on the geological condition of multiple coal seams mining in No.8 Colliery of Pingdingshan Coal Group, the behaviours of the front abutment pressure in each of the coal seams and the fixed abutment pressure are observed. The main cause of deformation and damage to the galleries is the increasing value of the valid load coefficient of the surrounding rock. The rational pillar width of the district raise is studied when its two side seams have been mined, and the layout question of district raise in the different set of seams is also studied. The conclusions derived from the study are useful guiding reference for the design of district raise layout in deep multiple coal seams mining. 6 refs., 3 figs., 1 tab.

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

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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.

Innovative Extraction Method for a Coal Seam with a Thick Rock-Parting for Supporting Coal Mine Sustainability

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Meng Li

2017-10-01

Full Text Available As thick rock partings delay the efficient mining of coal seams and constrain the sustainable development of coal mines, an innovative extraction method for a coal seam with thick rock parting was proposed. The coal seams were divided into different sub-zones according to the thickness of rock parting and then the sub-zones were mined by separately using three mining schemes involving full-seam mining, combined mining using backfill and caving (CMBC, and reducing height mining. Afterwards, the study introduced the basic mechanism and key devices for the CMBC and analysed the working state of the backfill support in detail. Moreover, the method for calculating the length of the backfill zone was proposed to design the length of backfill zone and the influences of four factors (including bulking coefficient of rock parting on the length of the backfill zone were also explored. By taking the No. 22203 panel, Buertai mine, Inner Mongolia, China as an example, the mined coal resource by using the CMBC extraction method will increase by 1.83 × 106 tons and the recovery ratio will rise from 56.2% to 92.4% compared with mining of the 2-2 upper coal seam alone. Moreover, by applying CMBC, a series of environmental and ecological problems caused by rock parting is reduced, which can improve the environment in mined areas. The research can provide technological guidance for mining panels of a coal seam with a thick rock parting and the disposal thereof under similar conditions.

Evaluation of coal bed methane potential of coal seams of Sawang ...

Indian Academy of Sciences (India)

This analysis shows that the maximum methane gas adsorbed in the coal sample CG-81 is 17 m3/t (Std. daf), at maximum pressure of 5.92 MPa ... vast coal reserves are ideal reservoirs for the gen- eration and accumulation of CBM. ... of gases in coal seams, such as, compression as free gas in the pore spaces, condensed ...

On the problem of technological innovations in driving preparatory workings in thin coal seams

Energy Technology Data Exchange (ETDEWEB)

Peknik, J

1980-03-01

Possibilities of mechanizing preparation of thin coal seams for longwall mining are discussed. Until now preparatory workings in the Ostrava Karvina coal region have been driven mainly by manual work or blasting. Tables show the total length of preparatory workings driven in the period 1973-1978 and the average advance of preparatory working per day and per shift. Factors influencing mechanization of preparatory working drivage are: geological disturbances, angle of seam inclination and its changes, thickness of the seam and strength of coal. Some types of mining machines which can be used for driving preparatory workings in thin, horizontal and inclined coal seams and produced in the USSR and United Kingdom are reviewed. Two sets of machines used in coal seams inclined up to 18 or 20 degrees are presented: KN produced in the USSR and 'In seam Miner' produced by the Dosco firm in the UK. Parameters of both machines are compared. The following Soviet machines for driving preparatory workings in inclined seams are also reviewed: 2 KNP (slope 45-80 degrees), KMD-72 (slope 45-80 degrees, height of the seam 0.6 m to 1.2 m), MRS-2 (slope 45-90 degrees, height of the seam 0.55 m to 1.0 m). (7 refs.) (In Czech)

On the quantitative determination of coal seam thickness by means of in-seam seismic surveys

Czech Academy of Sciences Publication Activity Database

Schott, W.; Waclawik, Petr

2015-01-01

Roč. 52, č. 10 (2015), s. 1496-1504 ISSN 0008-3674. [International Colloquium on Geomechanics and Geophysics /5./. Karolinka, 25.06.2014-27.06.2014] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : in-seam seismic (ISS) * ISS wave * Love wave * coal seam thickness * dispersion Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 1.877, year: 2015 http://www.nrcresearchpress.com/doi/full/10.1139/cgj-2014-0466#.VgqE1Zc70mt

Principles of integrated modeling of coal seam mining

Energy Technology Data Exchange (ETDEWEB)

Magda, R

1983-01-01

Mathematical modeling of underground coal mining is discussed. Construction of a mathematical model of an underground mine is analyzed. The model is based on integrating the elementary units (modules). A so-called elementary mining field is defined with the example of a longwall face. A model of an elementary coal seam zone is constructed by integrating the elementary mining fields (in time and space) and supplementing them with a suitable model of mine roadway structure. By integrating the elementary coal seam zones a model of mining level is constructed. Such a mathematical model is used for optimizing the selected mining parameters e.g. structure of mine roadways, size of a coal mine, and organizational scheme of underground mining in a mine or in a mine section using the standardized optimization criterion e.g. investment. Use of the integration model of underground mining for optimizing coal mine construction is evaluated. The following elements of investment and operating cost are considered: shaft excavation, shaft equipment, investment in mining sections, ventilation, mine draining etc. 1 reference.

Ge distribution in the Wulantuga high-germanium coal deposit in the Shengli coalfield, Inner Mongolia, northeastern China

Energy Technology Data Exchange (ETDEWEB)

Du, Gang [Key Laboratory of Marginal Sea Geology, Chinese Academy of Sciences (China)]|[Coal Geology Bureau of Inner Mongolia, Hohhot, 010051 (China); Zhuang, Xinguo [Institute of Sedimentary Basin and Mineral, Faculty of Earth Resources, China University of Geosciences, Hubei, 430074 (China)]|[State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Hubei, 430074 (China); Querol, Xavier; Izquierdo, Maria; Alastuey, Andres; Moreno, Teresa; Font, Oriol [Institute of Earth Science ' Jaume Almera' , CSIC, C/ LLuis Sole Sabaris s/n, 08028 Barcelona (Spain)

2009-03-01

The geological and geochemical controls of the Ge distribution in the Cretaceous Wulantuga high-Germanium coal deposit in the Shengli coal field, Inner Mongolia are investigated. This paper focuses mainly on the spatial distribution of the Ge contents in coal. The high-Ge coals mainly occur in three splits of the 6 coal in the southwestern part of the Shengli coal field. Mean germanium contents in the coal range from 32 to 820 {mu}g/g, with a mean value of 137 {mu}g/g, on a bulk coal basis (mean of 939 coal samples from 75 boreholes in the 6 coal seam) in an area of 2.2 km{sup 2}. The highest Ge content occurs SW of 6 coal seam, close to the margins of the coal basin, decreasing with a fan-shaped trend towards NW, the direction of the coal basin. There is an negative correlation between the mean Ge content and the thickness of the coal seam. Different distribution patterns of Ge content were found in vertical profiles. High Ge concentrations may occur in the middle parts of coal seams, at the bottom and/or the top of thick coal seams and inconspicuous variation. A major organic affinity was determined for Ge, with a special enriched in the banded bright and semibright coal. The high-Ge coals and the coalified wood in the sandstone overlaying the 6-1 coal highly enriched in Ge, As, Sb, W, Cs, Tl, Be, and Hg. The Late Jurassic silicified volcanic rocks in the NW of the Ge coal deposit relatively high enriched in Ge, Ga, Sb, As, Cs, Be, Ge and Hg. The correlation coefficients among the elements enriched showed marked variations at close sites in this deposit, suggesting a possible diagenetic origin of the geochemical anomaly. The main Ge anomaly was attributed to early Cretaceous hydrothermal fluids circulating through the fault systems and porous volcanic rocs, probably from the subjacent granitoid rocks. The fault systems, the porous coarse clastic rocks overlying coal seam and the lithotype of coal played an important role in the transport and trapping of Ge. A

System of the creation of a model for the coal deposit, and the subsequent

Directory of Open Access Journals (Sweden)

Staněk František

1996-09-01

Full Text Available In the paper, methodics of creating a model for different type of the coal deposit is described, including the processing of reserves text and graphic outputs. It is also useful in cases of the deposit with a great number of seams of various thicknesses that is heavily tectonically disturbed and divided into tectonic blocks. The development of seams is variable in both the thickness and quality. Splitting of the seams occurs, separate benches are formed and, on the contrary, connected into one seam.

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)

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. PMID:24396293

Depositional setting, petrology and chemistry of Permian coals from the Parana Basin: 2. South Santa Catarina Coalfield, Brazil

Energy Technology Data Exchange (ETDEWEB)

Kalkreuth, W.; Mexias, A.; Balbinot, M.; Levandowski, J. [Instituto de Geociencias, UFRGS, Porto Alegre (Brazil); Holz, M. [Inst. de Geociencias, UFBA, Salvador, Bahia (Brazil); Willett, J.; Finkelman, R. [U.S. Geological Survey, Reston, VA (United States); Burger, H. [Freie Universitaet Berlin, Geoinformatik, (Germany)

2010-12-01

In Brazil economically important coal deposits occur in the southern part of the Parana Basin, where coal seams occur in the Permian Rio Bonito Formation, with major coal development in the states of Rio Grande de Sul and Santa Catarina. The current paper presents results on sequence stratigraphic interpretation of the coal-bearing strata, and petrological and geochemical coal seam characterization from the South Santa Catarina Coalfield, Parana Basin. In terms of sequence stratigraphic interpretation the precursor mires of the Santa Catarina coal seams formed in an estuarine-barrier shoreface depositional environment, with major peat accumulation in a high stand systems tract (Pre-Bonito and Bonito seams), a lowstand systems tract (Ponta Alta seam, seam A, seam B) and a transgressive systems tract (Irapua, Barro Branco and Treviso seams). Seam thicknesses range from 1.70 to 2.39 m, but high proportions of impure coal (coaly shale and shaley coal), carbonaceous shale and partings reduce the net coal thickness significantly. Coal lithoypes are variable, with banded coal predominant in the Barro Branco seam, and banded dull and dull coal predominantly in Bonito and Irapua seams, respectively. Results from petrographic analyses indicate a vitrinite reflectance range from 0.76 to 1.63 %Rrandom (HVB A to LVB coal). Maceral group distribution varies significantly, with the Barro Branco seam having the highest vitrinite content (mean 67.5 vol%), whereas the Irapua seam has the highest inertinite content (33.8 vol%). Liptinite mean values range from 7.8 vol% (Barro Branco seam) to 22.5 vol% (Irapua seam). Results from proximate analyses indicate for the three seams high ash yields (50.2 - 64.2 wt.%). Considering the International Classification of in-Seam Coals, all samples are in fact classified as carbonaceous rocks (> 50 wt.% ash). Sulfur contents range from 3.4 to 7.7 wt.%, of which the major part occurs as pyritic sulfur. Results of X-ray diffraction indicate the

Thin seam mining

Energy Technology Data Exchange (ETDEWEB)

Sikora, W [Politechnika Slaska, Gliwice (Poland). Instytut Mechanizacji Gornictwa

1989-06-01

Discusses thin seam mining in Poland and its prospects. There were 194 working faces in coal seams to 1.5 m thick in Poland in 1988. Of them, 115 fell on faces with powered supports, 79 on faces with SHC-40 and Valent props; 108 shearer loaders and 45 coal plows were used for longwall mining of thin coal seams. Drilling and blasting was used to mine 21 working faces. Longwall faces in seams to 1.0 m thick gave 2.0% coal output, faces in coal seams 1.01-1.5 m thick gave 12.2% of daily coal output of underground mining. Structure of daily coal output of faces in thin seams was the following: 52 faces below 300 t/day, 42 from 301-500 t/day, 63 from 501 to 1,000 t/day, 17 faces above 1,000 t/day. Prospects for increasing coal output of faces in thin seams are discussed. 7 refs.

Modeling of Three Flat Coal Seams Strata Developing at Open Pit Miming

Science.gov (United States)

Gvozdkova, Tatiana; Markov, Sergey; Demirel, Nuray; Anyona, Serony

2017-11-01

The use of low-cost direct dumpling technology, as is well known, has a relatively limited field of application: flat coal seams, and the higher the dip angle of the seam, the more difficult it is to place the necessary volume of overburden rock in the dumping layers. For this, we have to pour four-tier dumps. In this article, four possible options for piling the dump have been studied and prerequisites have been made for further research aimed at improving the efficiency of the use of direct dumpling technology in the development of flat coal seams.

Method of gas emission control for safe working of flat gassy coal seams

Science.gov (United States)

Vinogradov, E. A.; Yaroshenko, V. V.; Kislicyn, M. S.

2017-10-01

The main problems at intensive flat gassy coal seam longwall mining are considered. For example, mine Kotinskaja JSC “SUEK-Kuzbass” shows that when conducting the work on the gassy coal seams, methane emission control by means of ventilation, degassing and insulated drain of methane-air mixture is not effective and stable enough. It is not always possible to remove the coal production restrictions by the gas factor, which leads to financial losses because of incomplete using of longwall equipment and the reduction of the technical and economic indicators of mining. To solve the problems, the authors used a complex method that includes the compilation and analysis of the theory and practice of intensive flat gassy coal seam longwall mining. Based on the results of field and numerical researches, the effect of parameters of technological schemes on efficiency of methane emission control on longwall panels, the non-linear dependence of the permissible according to gas factor longwall productivity on parameters of technological schemes, ventilation and degassing during intensive mining flat gassy coal seams was established. The number of recommendations on the choice of the location and the size of the intermediate section of coal heading to control gassing in the mining extracted area, and guidelines for choosing the parameters of ventilation of extracted area with the help of two air supply entries and removal of isolated methane-air mixture are presented in the paper. The technological scheme, using intermediate entry for fresh air intake, ensuring effective management gassing and allowing one to refuse from drilling wells from the surface to the mined-out space for mining gas-bearing coal seams, was developed.

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.

Law of Strata Pressure Behavior in Shallow Coal Seam

Science.gov (United States)

Zhao, Jian; Liu, Leibin; Zheng, Zhiyang

2018-02-01

The law of strata pressure behavior in shallow coal seam is analyzed, according to the load data of Jinjie Coal Mine 31109 working face hydraulic supports. The first weighting distance of main roof is 80 m, and the periodic weighting distance of main roof is about 20 m. And according to the load data in the middle and both ends of the working face, the working resistance of hydraulic supports and the setting load are a bit small, so they couldn’t meet the needs of supporting roof. Then, the front abutment pressure of working face is analyzed by numerical simulation. It does not only explain the reason that the load is too big, but also explains the reason that the strata pressure behavior in shallow coal seam is serious. The length of undamaged main roof rock beam verifies the correctness of the periodic weighting distance.

Stress distribution characteristics in the vicinity of coal seam floor

Science.gov (United States)

Cui, Zimo; Chanda, Emmanuel; Zhao, Jingli; Wang, Zhihe

2018-01-01

Although longwall top-coal caving (LTCC) has been a popular, more productive and cost-effective method in recent years, roadway floor heave and rock bursts frequently appear when exploiting such coal seams with large dip angle. This paper proposes addressing this problem by adopting three-dimensional roadway layout of stagger arrangement (3-D RLSA). In this study, the first step was to analyse the stress distribution characteristics in the vicinity of coal seam floor based on the stress slip line field theory. In the second step, numerical calculation using FLAC3D was conducted. Finally, an evaluation of the 3-D RLSA for solving this particular issue was given. Results indicate that for this particular mine the proposed 3-D RLSA results in 24% increase in the coal recovery ratio and a modest reduction in excavation and maintenance costs compared to the conventional LTCC method.

Spatio-temporal evolution of apparent resistivity during coal-seam hydraulic flushing

Science.gov (United States)

Li, Dexing; Wang, Enyuan; Song, Dazhao; Qiu, Liming; Kong, Xiangguo

2018-06-01

Hydraulic flushing in gas predrainage is widely used, but the hydraulic-flushing effect is evaluated in a traditional way, by determining the desorption volume, moisture content, gas drainage rate and other conventional indices. To verify the rationality and feasibility of the multielectrode resistivity method in the evaluation of coal-seam hydraulic flushing and to research the spatio-temporal evolution of apparent resistivity during hydraulic flushing, a field test was conducted in 17# coal seam at Nuodong Mine, Guizhou. During hydraulic flushing, four stages were defined according to the variation in coal rock resistivity with time, namely, the preparation stage, the sharply decreasing stage, the rapidly increasing stage and the steady stage. The apparent resistivity of the coal rock mass is affected mainly by its own degree of fragmentation and flushing volume. A more serious rupture and a greater flushing volume yield a smaller apparent resistivity during the sharply decreasing stage and a higher resistivity during the stable stage. After three months of gas predrainage, the residual gas content and the gas pressure at different points in the expected affected area decrease below the critical value. Changes in the residual gas content and gas pressure at these points are consistent with the apparent resistivity, which validates the rationality and feasibility of the multielectrode resistivity method in evaluating coal-seam hydraulic flushing.

Detecting voids in coal seams in surface mining by means of a biophysical method

Energy Technology Data Exchange (ETDEWEB)

Bek, E.

1985-07-01

Soviet research institutes, in cooperation with research intitutes from other countries, developed the Radar 1 system for detecting abandoned workings in coal seams in surface mines. The system will be used for detecting voids in seams at depths to 50 m. The Academy of Sciences of Czechoslovakia tested use of dowsing for detecting abandoned workings in the Pohranicni straz, the Brezova and the Medard coal surface mines. The workings were situated at depths from 2 to 12 m from the ground surface (dowser position). The dowser was not informed of position or dimensions of the workings. Accuracy of determining position of abandoned workings in coal seams was high. Results of dowsing were checked by drilling. 4 references.

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

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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.

The age, palaeoclimate, palaeovegetation, coal seam architecture/mire types, paleodepositional environments and thermal maturity of syn-collision paralic coal from Mukah, Sarawak, Malaysia

Science.gov (United States)

Sia, Say-Gee; Abdullah, Wan Hasiah; Konjing, Zainey; Koraini, Ahmad Munif

2014-02-01

The Mukah coal accumulated in the Balingian Formation where the time-stratigraphic position is poorly defined by fauna, though a probable Late Miocene age has always been assigned to this formation. Samples collected in the present study that yielded an abundance of Casuarina pollen associated with occurrences of Dacrydium, Stenochlaena palustris, Florschuetzia levipoli and also Stenochlaena areolaris spores, compare closely to zone PR9 of the palynological zonation of the Malay Basin, and can be tied to depositional sequences of Malay Basin Seismic sequences I2000/I3000, indicating an Early Miocene age for the studied coal. The Early Miocene age shows that the Mukah coal was formed during the collision between Luconia Block-Dangerous Grounds with the Borneo that lasted from Late Eocene to late Early Miocene. The rapid increase of deposition base-level caused by the collision is clearly reflected by the architecture of the Mukah coal seams that were generally thin, and also by the reverse order of the paleo-peat bodies.

Effects of torpedo blasting on rockburst prevention during deep coal seam mining in the Upper Silesian Coal Basin

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Ł. Wojtecki

2017-08-01

Full Text Available In the Upper Silesian Coal Basin (USCB, coal seams are exploited under progressively more difficult geological and mining conditions (greater depth, higher horizontal stress, more frequent occurrence of competent rock layers, etc.. Mining depth, dislocations and mining remnants in coal seams are the most important factors responsible for the occurrence of rockburst hazards. Longwall mining next to the mining edges of neighbouring coal seams is particularly disadvantageous. The levels of rockburst hazards are minimised via the use of rockburst prevention methods. One active prevention method is torpedo blasting in roof rocks. Torpedo blastings are performed in order to decrease local stress concentrations in rock masses and to fracture the roof rocks to prevent or minimise the impact of high-energy tremors on excavations. The estimation of the effectiveness of torpedo blasting is particularly important when mining is under difficult geological and mining conditions. Torpedo blasting is the main form of active rockburst prevention in the assigned colliery in the Polish part of the USCB. The effectiveness of blasting can be estimated using the seismic effect method, in which the seismic monitoring data and the mass of explosives are taken into consideration. The seismic effect method was developed in the Czech Republic and is always being used in collieries in the Czech part of the coal basin. Now, this method has been widely adopted for our selected colliery in the Polish part of the coal basin. The effectiveness of torpedo blastings in the faces and galleries of the assigned longwall in coal seam 506 has been estimated. The results show that the effectiveness of torpedo blastings for this longwall was significant in light of the seismic effect method, which corresponds to the in situ observations. The seismic effect method is regularly applied to estimating the blasting effectiveness in the selected colliery.

Coal seam has boom - powering North Queensland industrial growth

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-06-01

Reduced operating costs, lower greenhouse gas emissions and security of supply are being cited by North Queensland industry leaders as the reasons for investing more than A$550 million to expand operations and convert to coal seam gas as their preferred fuel source. The article, by Enertrade, reports that just a few months after commissioning its North Queensland Gas Pipeline to transport coal seam gas from Moranbah to Townsville, Enertrade has signed contracts that will see combined cycle gas-fired baseload electricity generated in Townsville and the Queensland Nickel Refinery, and Xstrata Copper Refinery switch from liquid fuels to gas. The development has been driven by state government policy that 13% of Queensland's electricity be sourced from gas-fired power generation from 1 January 2005. Further information is available from Enertrade on Tel +617 3331 9929. 2 photos.

The Method of Validity Evaluation of Hard Coal Excavation in Residual Seam Parts

Science.gov (United States)

Wodarski, Krzysztof; Bijańska, Jolanta; Gumiński, Adam

2017-12-01

The excavation of residual seam parts should be justified by positive assessment of the purposefulness, technical feasibility and economic effectiveness. The results of the profitability evaluation are crucial in a decision making process. The excavation of residual seam parts, even if it is possible from a technical point of view, should not be implemented if it is economically inefficient or when accompanied by a very high risk of non-recovery of invested capital resources. The article presents the evaluation method of possibilities of excavating hard coal from residual seam parts, and the example of its use in one of collieries in the Upper Silesian Coal Basin. Working in line with the developed method, allows to indicate the variant of residual seam part exploitation, which is feasible to implement from a technical point of view, and which is characterized by the highest economic effectiveness and lowest risk.

Analysis of support installation and strata control in ventilation tunnels and coal chutes in steep seams

Energy Technology Data Exchange (ETDEWEB)

Moroz, V D; Belyaev, A N; Kostyuk, I S

1984-01-01

The VNIMI and the Donugi branch in Gorlovka developed and tested a system for strata control in gate roads for ventilation and in coal chutes in inclined and steep medium and thick coal seams. The roof is supported by cribbings made of slabs of reinforced concrete with yielding elements. Timber is used as yielding material. Tests showed that thickness of yielding layers between concrete slabs should range from 15 to 20% of coal seam thickness. Yielding elements increase yield strength of the system to about 2 MN (load distribution is more regular). The tests show that the cribbings are an efficient system for strata control in workings driven in coal seams with dip angle from 35 to 60 degrees. Performance of concrete cribbings in ventilation gate roads and coal chutes in selected mines of the Ukrainian SSR is analyzed.

A comparison of geochemical features of extracts from coal-seams source rocks with different polarity solvents

Energy Technology Data Exchange (ETDEWEB)

Chen, Jianping; Deng, Chunping; Wang, Huitong

2009-02-15

There exists a great difference in group-type fractions and biomarker distributions of chloroform extracts from coals and coal-seams oils, which makes the source identification of coal-seams oils in sedimentary basins rather difficult. The experiment, in which four different polarity solvents, n-hexane, benzene, dichloromethane and chloroform, were used to extract 9 coal-seams source rocks and 3 typical lacustrine source rocks, showed that the yield of extracts increased gradually with increasing solvent polarity. The distribution features of their n-alkanes, isoprenoids and sterane and terpane biomarkers remained, in general, similar, showing no distinct enrichment or depletion for a certain fraction by any solvent. The compositional analysis on n-hexane and chloroform extracts showed that the absolute amount (concentration) of biomarkers was relatively low for the n-hexane extract but comparatively high for the chloroform extract, this difference became great among coal-seams source rocks but small among lacustrine mudstones. The statistical analysis on the relative amount of the 18 major biomarkers in n-hexane and chloroform extracts from 10 source rock samples showed that extracts with a proportional error for the same biomarker of less than 5% (including the analytical error) accounted for 84% while those with a proportional error over 10% amounted to below 5%. This suggested that the outcome of oil-source correlation made by these biomarkers will be independent of variations in amounts of saturates and biomarkers arising from solvent polarity. Therefore, biomarkers obtained from organic-rich source rocks including coals by the extraction with the commonly used chloroform solvent can be applied for the oilsource correlation of coal-seams petroliferous basins.

Palynological dating of a coal seam in Ayyanapalem area, Khamman District, Andhra Pradesh, India

Energy Technology Data Exchange (ETDEWEB)

Rao, M.R.; Lakshminarayana, G.; Ramanujam, C.G.K. (Geological Survey of India, Hyderabad (India). Southern Region)

1990-05-25

A palynological study of five subsurface samples of a coal seam near Ayyanapalem, Chintalapudi sub-basin of Godavari valley, Andhra Pradesh, was carried out. Twenty-five genera, including monosaccate, striate and nonstriate bisaccate, and trilete sporomorphs were identified; striate bisaccates predominate. Based on occurrence of {ital Rhizomaspora, Microbaculispora, Indotriradites, Crucisaccites ital} and {ital Corisaccites}, the coal seam is inferred to be similar in age to the Permian age Barakar Formation of the Lower Gondwana. 3 refs., 2 figs.

Methods for working thick seams and research on increasing their effectiveness

Energy Technology Data Exchange (ETDEWEB)

Sikora, W

1976-01-01

In Poland nearly 40 per cent of all coal is extracted from seams more than 3 m. thick. In absolute figures this represents about 70 million tons of coal per year. Working seams with thicknesses up to 3.5 m. does not present, at present, major difficulties. Working thicker seams calls for a steady improvement in order to increase the degree of utilizaion of the deposit and to enlarge the concentration of output. The seams are worked under protected surface structures which compels the mines to use hydraulic stowing with all its advantages and disadvantages. Rock burst hazard, the control of which is the basic problem hindering the mining, is a further problem. 3 refs.

3D Discrete element approach to the problem on abutment pressure in a gently dipping coal seam

Science.gov (United States)

Klishin, S. V.; Revuzhenko, A. F.

2017-09-01

Using the discrete element method, the authors have carried out 3D implementation of the problem on strength loss in surrounding rock mass in the vicinity of a production heading and on abutment pressure in a gently dripping coal seam. The calculation of forces at the contacts between particles accounts for friction, rolling resistance and viscosity. Between discrete particles modeling coal seam, surrounding rock mass and broken rocks, an elastic connecting element is introduced to allow simulating coherent materials. The paper presents the kinematic patterns of rock mass deformation, stresses in particles and the graph of the abutment pressure behavior in the coal seam.

Preparation and extraction of sloping seams without leaving inter-drift coal pillars

Energy Technology Data Exchange (ETDEWEB)

Artamonov, N S; Bormotov, I N; Brovko, I I

1977-10-01

A description is given of mining three coal seams in the Kuznetsk Basin without leaving coal pillars because they could not withstand the stress of the induced reference pressure. This system reduced coal losses in 1976 in comparison to 1970 and eliminated local accumulations of methane by withdrawing it through the excavated area. The system was noted to have the disadvantage of additional expenditures for timber supports. 2 figures.

Determination of mineral matter distribution in a coal seam using O sub 2 chemisorption technique

Energy Technology Data Exchange (ETDEWEB)

Palmer, A.D.; Goulet, J.-C.; Grandsen, J.; Price, J.T.; Furimsky, E. (CANMET, Ottawa, ON (Canada). Energy Research Laboratories)

1990-08-01

A series of samples taken from different depths of the seam of a bituminous coal in Western Canada was used to determine the mineral matter distribution. The measurements were carried out using the O{sub 2} chemisorption based on a thermogravimetric technique. The O{sub 2} chemisorption increased with decreasing mineral matter content. The employed technique was found to be suitable for identifying the portion of coal seam least contaminated with mineral matter. 5 refs., 3 figs., 1 tab.

Geological storage of carbon dioxide in the coal seams: from material to the reservoir

International Nuclear Information System (INIS)

Nikoosokhan, S.

2012-01-01

CO 2 emissions into the atmosphere are recognized to have a significant effect on global warming. Geological storage of CO 2 is widely regarded as an essential approach to reduce the impact of such emissions on the environment. Moreover, injecting carbon dioxide in coal bed methane reservoirs facilitates the recovery of the methane naturally present, a process known as enhanced coal bed methane recovery (ECBM). But the swelling of the coal matrix induced by the preferential adsorption by coal of carbon dioxide over the methane in place leads to a closure of the cleat system (a set of small natural fractures) of the reservoir and therefore to a loss of injectivity. This PhD thesis is dedicated to a study of how this injectivity evolves in presence of fluids. We derive two poro-mechanical dual-porosity models for a coal bed reservoir saturated by a pure fluid. The resulting constitutive equations enable to better understand and model the link between the injectivity of a coal seam and the adsorption-induced swelling of coal. For both models, the pore space of the reservoir is considered to be divided into the macroporous cleats and the pores of the coal matrix. The two models differ by how adsorption of fluid is taken into account: the first model is restricted to surface adsorption, while the second model can be applied for adsorption in a medium with a generic pore size distribution and thus in a microporous medium such as coal, in which adsorption mostly occurs by micropore filling. The latter model is calibrated on two coals with different sorption and swelling properties. We then perform simulations at various scales (Representative Elementary Volume, coal sample, coal seam). In particular, we validate our model on experimental data of adsorption-induced variations of permeability of coal. We also perform simulations of seams from which methane would be produced (CBM) or of methane-free seams into which CO 2 would be injected. We study the effect of various

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

Energy Technology Data Exchange (ETDEWEB)

Wang, W.F.; Qin, Y.; Song, D.Y.; Sang, S.X.; Jiang, B.; Zhu, Y.M.; Fu, X.H. [China University of Mining & Technology, Xuzhou (China). College for Resources & Geoscience

2005-12-15

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 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. 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 kaolinite, 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, AI, 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.

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…

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

Phosphorus minerals in tonstein; coal seam 405 at Sośnica-Makoszowy coal mine, Upper Silesia, southern Poland

Science.gov (United States)

Kokowska-Pawłowska, Magdalena; Nowak, Jacek

2013-06-01

Kokowska-Pawłowska, M. and Nowak, J. 2013. Phosphorus minerals in tonstein; coal seam 405 at Sośnica- Makoszowy coal mine, Upper Silesia, southern Poland. Acta Geologica Polonica, 63 (2), 271-281. Warszawa. The paper presents results of research on tonstein, which constitutes an interburden in coal seam 405 at the Sośnica- Makoszowy coal mine, Makoszowy field (mining level 600 m), Upper Silesia, southern Poland. The mineral and chemical compositions of the tonstein differ from the typical compositions described earlier for tonsteins from Upper Silesia Coal Basin area. Additionally, minerals present in the tonsteins include kaolinite, quartz, kaolinitised biotite and feldspars. The presence of the phosphatic minerals apatite and goyazite has been recognized. The presence of gorceixite and crandallite is also possible. The contents of CaO (5.66 wt%) and P2O5 (6.2 wt%) are remarkably high. Analysis of selected trace elements demonstrated high contents of Sr (4937 ppm) and Ba (4300 ppm), related to the phosphatic minerals. On the basis of mineral composition the tonstein has been identified as a crystalline tonstein, transitional to a multiplied one.

Influence of a Large Pillar on the Optimum Roadway Position in an Extremely Close Coal Seam

Directory of Open Access Journals (Sweden)

Li Yang

2016-01-01

Full Text Available Based on the mining practice in an extremely close coal seam, theoretical analysis was conducted on the vertical stress distribution of the floor strata under a large coal pillar. The vertical stress distribution regulation of a No. 5 coal seam was revealed. To obtain the optimum position of the roadway that bears the supporting pressure of a large coal pillar, numerical modeling was applied to analyze the relation among the stress distribution of the roadway surrounding the rock that bears the supporting pressure of a large coal pillar, the plastic zone distribution of the roadway surrounding the rock, the surrounding rock deformation, and the roadway layout position. The theoretical calculation results of the stress value, stress variation rate, and influencing range of the stress influencing angle showed that the reasonable malposition of the No. 5 coal seam roadway was an inner malposition of 4 m. The mining practice showed the following: the layout of No. 25301 panel belt roadway at the position of the inner malposition of 4 m was reasonable, the roadway support performance was favourable without deformation, and ground pressure was not obvious. The research achievement of this study is the provision of a reference for roadway layouts under similar conditions.

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.

Selection of an Appropriate Mechanized Mining Technical Process for Thin Coal Seam Mining

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Chen Wang

2015-01-01

Full Text Available Mechanized mining technical process (MMTP related to the control method of the shearer is a vital process in thin coal seam mining operations. An appropriate MMTP is closely related to safety, productivity, labour intensity, and efficiency. Hence, the evaluation of alternative MMTP is an important part of the mining design. Several parameters should be considered in MMTP evaluation, so the evaluation is complex and must be compliant with a set of criteria. In this paper, two multiple criteria decision-making (MCDM methods, Analytic Hierarchy Process (AHP and Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE, were adopted for this evaluation. Then, the most appropriate MMTP for a thin coal seam working face was selected in China.

An influence function method based subsidence prediction program for longwall mining operations in inclined coal seams

Energy Technology Data Exchange (ETDEWEB)

Yi Luo; Jian-wei Cheng [West Virginia University, Morgantown, WV (United States). Department of Mining Engineering

2009-09-15

The distribution of the final surface subsidence basin induced by longwall operations in inclined coal seam could be significantly different from that in flat coal seam and demands special prediction methods. Though many empirical prediction methods have been developed, these methods are inflexible for varying geological and mining conditions. An influence function method has been developed to take the advantage of its fundamentally sound nature and flexibility. In developing this method, significant modifications have been made to the original Knothe function to produce an asymmetrical influence function. The empirical equations for final subsidence parameters derived from US subsidence data and Chinese empirical values have been incorporated into the mathematical models to improve the prediction accuracy. A corresponding computer program is developed. A number of subsidence cases for longwall mining operations in coal seams with varying inclination angles have been used to demonstrate the applicability of the developed subsidence prediction model. 9 refs., 8 figs.

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

Energy Technology Data Exchange (ETDEWEB)

En-yuan Wang; Xiao-fei Liu; En-lai Zhao; Zhen-tang Liu [China University of Mining and Technology, Xuzhou (China). School of Safety Engineering

2009-06-15

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 eliminating abnormal gas emission by eliminating the occurrence of rock burst or depressing the magnitude of rock burst was considered. The No.237 working face in Nanshan coal mine was selected as the typical working face contacting gas in deep mining; aimed at this working face, a system of rock burst prediction and control for coal seam contacting gas in deep mining was established using the three-dimensional distinct element code software 3DEC. 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 burts control by an electromagnetic radiation method and specific drilling method. 8 refs., 4 figs., 1 tab.

"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…

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.

Coal Mining and Coal Seam Gas on Gomeroi country: Sacred lands, economic futures and shifting alliances

International Nuclear Information System (INIS)

Norman, Heidi

2016-01-01

North western NSW has seen a host of interest groups working in alliance opposing coal and coal seam gas mining. These groups - farmers, residents and environmentalists share concerns about the impact on the unique black soil and aquifer, of fossil fuel more broadly. While these shared alliances across class, gender and generations are emergent, Aboriginal citizens are uniquely placed in this contest over land, environment and resources. This paper sets out to show the historical and contemporary significance of the place of Aboriginal people in the debate over land use, arguing that, for the first time in history, Aboriginal worlds are central to community futures. In this space, new relationships are being forged and new discourse is required to comprehend the complex position Aboriginal citizens have as custodians of place and at the same time, the responsibility to provide for families and communities, otherwise excluded from the prevailing modern economy. With reference to the history of both relationship to land and land usage over Gomeroi country, and drawing on ethnographic along with archival research, this article seeks to contribute to a critical understanding of Aboriginal people's dealings in relation to their land, their cultural and economic interests with in an emerging regional coal economy, and in turn how they are redefining the context for energy resource extraction, and energy policy. - Highlights: • Aboriginal worlds are central to community futures in Australia. • Prospecting for coal and coal seam gas is forcing Aboriginal land holders into new relationships. • The nexus between the coal economy & Aboriginal self-determination is deeply contested. • New discourses are emerging to comprehend the custodianship of place in the context of mining.

Field trials of aquifer protection in longwall mining of shallow coal seams in China

Energy Technology Data Exchange (ETDEWEB)

Zhang, D.S.; Fan, G.W.; Liu, Y.D.; Ma, L.Q. [State Key Laboratory of Coal Resource & Mine Safety, Xuzhou (China)

2010-09-15

The large-scale mining of shallow coal seams has a significant impact on the overlying aquifers and surface ecological environment. To protect the aquifers and maximize the coal resource recovery, field trials were undertaken during the operation of the LW32201 in Bulianta coal mine, Shendong, China. With a severely weathered rock (SWR) layer and two key strata (KS) in the overlying strata, aquifer protection in longwall mining (APLM) relies mainly on the rapid advance. In some localized zones, special measures should be taken to achieve the APLM, including lowering mining height, backfill and slurry injection. To further understand the mechanism and applicable conditions of the APLM and validate the effectiveness of the APLM, variation of the water table in the aquifer was observed as the longwall face passed through the zone. This paper also discusses the mechanism and basic requirements of the APLM and the relationship between the fall of the water table and the surface subsidence. The results of the field trials indicated that APLM in shallow coal seams could be successful under suitable conditions.

Development of the first coal seam gas exploration program in Indonesia: Reservoir properties of the Muaraenim Formation, south Sumatra

Energy Technology Data Exchange (ETDEWEB)

Sosrowidjojo, I.B. [R and D Centre for Oil and Gas Technology, LEMIGAS, Jakarta (Indonesia); Saghafi, A. [CSIRO Energy Technology, P O Box 330, Newcastle, NSW, 2300 (Australia)

2009-09-01

The Late Miocene Muaraenim Formation in southern Sumatra contains thick coal sequences, mostly of low rank ranging from lignite to sub-bituminous, and it is believed that these thick low rank coals are the most prospective for the production of coal seam gas (CSG), otherwise known as coalbed methane (CBM), in Indonesia. As part of a major CSG exploration project, gas exploration drilling operations are being undertaken in Rambutan Gasfields in the Muaraenim Formation to characterize the CSG potential of the coals. The first stage of the project, which is described here, was designed to examine the gas reservoir properties with a focus on coal gas storage capacity and compositional properties. Some five CSG exploration boreholes were drilled in the Rambutan Gasfield, south of Palembang. The exploration boreholes were drilled to depths of {proportional_to} 1000 m into the Muaraenim Formation. Five major coal seams were intersected by these holes between the depths of 450 and 1000 m. The petrography of coal samples collected from these seams showed that they are vitrinite rich, with vitrinite contents of more than 75% (on a mineral and moisture free basis). Gas contents of up to 5.8 m{sup 3}/t were measured for the coal samples. The gas desorbed from coal samples contain mainly methane (CH{sub 4}) ranging from 80 to 93% and carbon dioxide (CO{sub 2}) ranging from 6 to 19%. The composition of the gas released into the production borehole/well is, however, much richer in CH{sub 4} with about 94 to 98% CH{sub 4} and less than 5% CO{sub 2}. The initial results of drilling and reservoir characterization studies indicate suitable gas recovery parameters for three of the five coal seams with a total thickness of more than 30 m. (author)

Detecting voids in a 0. 6m coal seam, 7m deep, using seismic reflection

Energy Technology Data Exchange (ETDEWEB)

Miller, R.D.; Steeples, D.W. (University of Kansas, Lawrence, KS (USA). Kansas Geological Survey)

1991-07-01

Surface collapse over abandoned subsurface coal mines is a problem in many parts of the world. High-resolution P-wave reflection seismology was successfully used to evaluate the risk of an active sinkhole to a main north-south railroad line in an undermined area of southeastern Kansas, USA. Water-filled cavities responsible for sinkholes in this area are in a 0.6 m thick coal seam, 7 m deep. Dominant reflection frequencies in excess of 200 Hz enabled reflections from the coal seam to be discerned from the direct wave, refractions, air wave, and ground roll on unprocessed field files. Repetitive void sequences within competent coal on three seismic profiles are consistent with the 'room and pillar' mining technique practiced in this area near the turn of the century. The seismic survey showed that the apparent active sinkhole was not the result of reactivated subsidence but probably the results of erosion. 14 refs., 6 figs.

New method for protecting mine roadways in thin coal seams by means of prefabricated yielding blocks

Energy Technology Data Exchange (ETDEWEB)

Peknik, J

1983-05-01

The use of concrete blocks for strata control in mine roadways driven in thin coal seams is evaluated. Two types of prefabricated blocks are used: BZT blocks made of reinforced concrete and yielding elements or popilbet blocks made of a mixture of fly ash (from coal power plants) and concrete. When the popilbet blocks were used no yielding elements were necessary. Mechanical properties of blocks made of reinforced concrete were controlled by yielding elements. Mechanical properties (compression strength) of the popilbet blocks were controlled by proportion of water, cement and fly ash. The BZT and the popilbet blocks were used for strata control in mine roadways in coal seams from 60 to 80 cm thick and dip angle from 5 to 18 degrees. Use of the BZT and the popilbet blocks reduced roadway deformation by about 50% in comparison to traditional strata control methods (timber cribbings, use of waste rock, etc.). Use of the blocks is explained. The BZT and the popilbet blocks were placed in a roadway wall. Height of the block wall equaled coal seam thickness. Yielding arched steel supports and timber liners were used for strata control in the roadway. The popilbet blocks were 50% less expensive than the BZT blocks. 9 references

Study of geological and technologic evaluation for steeply inclined coal seams

Energy Technology Data Exchange (ETDEWEB)

Zhang Xiao-bing; Wang Zhong-qiang; Zhang Wei (and others) [China University of Mining & Technology, Beijing (China). School of Resources and Safety Engineering

2007-07-01

In order to predict the mining effect and choice of the technical decision comprehensive evaluation on steep coal seams was taken. Based on technical test, mining practice and analysis of statistic data, the hierarchical structure of evaluation about steeply inclined coal seam was obtained. In the structure, there are 8 multiple factors, which can divide 13 fundamental factors. Using the method of comprehensive evaluation with multi-index and fuzzy mathematics, the evaluation functions of the influencing factors are structured, and the model of fuzzy evaluation is proposed. 289 mining faces in Datai mine were evaluated using this model and the single outputs of these faces were predicted. The result shows that the number of mining faces in the first class is 27, covering 9.43% of the total, the number of the second class is 87, covering 30.1% of the total, the number of the third class is 112, covering 38.75%, and the number of the fourth class is 63, covering 21.8%.The evaluation and the reality are largely uniform. 8 refs., 3 tabs.

Biological action of coal dust formed during excavation of seams after physicochemical treatment

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, V V; Gadzhiev, G P

1982-03-01

Destruction of the self-cleansing function of lungs by dust is important in the development of pneumoconiosis. It is expedient to study the influence of chemical substances, injected into coal seams to prevent methane bursts and reduce dust formation, on the physiologic mechanisms for the protection of the lungs from dust (macrophageal reaction of lungs, function of mucociliary transport). An investigation using 15, 24 and 50% solutions of binder KM/SUB/2 modified by polyvinyl alcohol, and 3% hydrochloric acid solution was conducted on 200 white rats. Reaction of rats treated with solutions of binder in different concentrations proved that accumulation of dust in lungs and lymph nodes was directly related to the strength of the solution. Three percent hydrochloric acid solution diminished dust accumulation in paratracheal lymph nodes and content of lipids and collagen in the lungs. Inhalation of dust treated with a 50% solution of binder KM/SUB/2 increases the deposit of dust in the lungs and increases fiber production. Therefore, solutions of more than 24% binder should not be used to treat coal. Solutions of 15% and 24% do not significantly affect the process of dust accumulation in the lungs. A 3% solution of hydrochloric acid reduces the dust-forming capacity of the coal mass. (13 refs.) (In Russian)

Coiled-tubing fracturing of coal seams on the Vermejo Park Ranch

Energy Technology Data Exchange (ETDEWEB)

Bybee, K.

2003-06-01

Coiled-tubing (CT) fracturing currently is used to stimulate the Vermejo and Raton coal seams on the Vermejo Park Ranch in northern New Mexico. The CT fracturing process increased the number of stimulation stages from 4 to 18 per well. CT fracturing results in more accurate proppant placement and more effective stimulation of the producing zones.

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.

Time-Lapse Analysis of Methane Quantity in the Mary Lee Group of Coal Seams Using Filter-Based Multiple-Point Geostatistical Simulation.

Science.gov (United States)

Karacan, C Özgen; Olea, Ricardo A

2013-08-01

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. The systematic approach presented in this paper is the first time in literature that history matching, TIs of GIPs and filter simulations are used for degasification performance evaluation and for assessing GIP for mining safety. Results from this study showed that using production history matching of coalbed methane wells to determine time-lapsed reservoir data could be used to compute spatial GIP and representative GIP TIs generated through Voronoi decomposition

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.

An Innovative Approach for Gob-Side Entry Retaining in Thick Coal Seam Longwall Mining

Directory of Open Access Journals (Sweden)

Manchao He

2017-11-01

Full Text Available Gob-side entry retaining (GER is a popular non-pillar mining technique regarding how to reserve a gateroad for the use of next panel mining. When used in thick coal seams, the conventional entry retaining method requires a huge amount of filling materials and may cause entry (gateroad accidents. Thus, an innovative non-pillar longwall mining approach is introduced. First, structural and mechanical models were built to explore the mechanism of the new approach. The modeling results indicate that effective bulking of the gob roof and reasonable support of the entry roof were key governing factors in improving entry stabilities and reducing roof deformations. Accordingly, a directional roof fracturing technique was proposed to contribute to gob roof caving, and a constant resistance and large deformation anchor (CRLDA cable was used to stabilize the entry roof. Subsequently, the evolutionary laws of the roof structure and stresses were explored using numerical simulation. It was found that the structure of the surrounding rocks around the retained entry changed significantly after roof fracturing. The stress-bearing center was transferred to the gob area, and the entry roof was in a low stress environment after adopting the approach. Finally, the approach was tested on a thick coal seam longwall mining panel. Field monitoring indicates that the retained entry was in a stable state and the index of the retained entry met the requirement of the next mining panel. This work provides an effective and economical approach to non-pillar longwall mining in thick coal seams.

Case study on ground surface deformation induced by CO2 injection into coal seam

International Nuclear Information System (INIS)

Li Hong; Tang Chun'an

2010-01-01

To monitor a geomechanical response of injecting CO 2 into relatively shallow coal seams, tiltmeters were set as an array to cover the ground surface area surrounding the injection well, and to measure the ground deformation during a well fracturing stimulation and a short-term CO 2 injection test. In this paper, an attempt to establish a quantitative relationship between the in-situ coal swelling and the corresponding ground deformation was made by means of numerical simulation study. (authors)

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

Science.gov (United States)

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

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. PMID:25866840

A sequential approach to control gas for the extraction of multi-gassy coal seams from traditional gas well drainage to mining-induced stress relief

International Nuclear Information System (INIS)

Kong, Shengli; Cheng, Yuanping; Ren, Ting; Liu, Hongyong

2014-01-01

Highlights: • The gas reservoirs characteristics are measured and analyzed. • A sequential approach to control gas of multi-gassy coal seams is proposed. • The design of gas drainage wells has been improved. • The utilization ways of different concentrations of gas production are shown. - Abstract: As coal resources become exhausted in shallow mines, mining operations will inevitably progress from shallow depth to deep and gassy seams due to increased demands for more coal products. However, during the extraction process of deeper and gassier coal seams, new challenges to current gas control methods have emerged, these include the conflict between the coal mine safety and the economic benefits, the difficulties in reservoirs improvement, as well as the imbalance between pre-gas drainage, roadway development and coal mining. To solve these problems, a sequential approach is introduced in this paper. Three fundamental principles are proposed: the mining-induced stress relief effect of the first-mined coalbed should be sufficient to improve the permeability of the others; the coal resource of the first-mined seams must be abundant to guarantee the economic benefits; the arrangement of the vertical wells must fit the underground mining panel. Tunlan coal mine is taken as a typical example to demonstrate the effectiveness of this approach. The approach of integrating surface coalbed methane (CBM) exploitation with underground gas control technologies brings three major benefits: the improvement of underground coal mining safety, the implementation of CBM extraction, and the reduction of greenhouse gas emissions. This practice could be used as a valuable example for other coal mines having similar geological conditions

Interplay of salt dynamics, sea-level change and climate on the depositional evolution of a Paleogene economic coal bearing salt rim syncline, Schoeningen, Germany

Energy Technology Data Exchange (ETDEWEB)

Osman, A.; Pollok, L.; Brandes, C.; Winsemann, J. [Leibniz Univ. Hannover (Germany). Inst. fuer Geologie

2013-08-01

The Paleogene basin fill (maximum 300 m thick) of the Schoeningen rim syncline in northern Germany is well known for its economic lignitic coal deposits. The fill provides an example of the interaction of basin subsidence, sea-level, and climate changes on depositional environment and gives insight into the development of the coal seams within a sequence stratigraphic context. The rim syncline records thirteen Lower to Middle Eocene coal seams with intervening clastic layers that were deposited during a long-lived transgression of the Central German Estuary, which lasted until the Late Oligocene (Standke, 2008). The previous analysis of the rim syncline fill has primarily focused on coal deposits, their lateral extent and paleo-botanical habitat. In this work, 357 lithologic logs were calibrated to outcrop profiles and integrated with previous studies to provide a facies analysis and sequence stratigraphy interpretation of the syncline fill. This improves understanding of the depositional environments of the lesser-studied clastics that intervene the coals (Osman et al., in review). Four 3{sup rd} order sequences are recorded in the Lower to Middle Eocene basin fill. Sequences 1 and 2 document the interplay of sands and coals within a transgressive estuarine phase. The sands show a regime change from tide- to more wave-dominated estuarine conditions before a turnaround to a regressive deltaic phase. This succession typifies an incised valley fill. However, the accommodation space generated for the initial estuary development is thought to have originated via continual salt withdrawal (Brandes et al. 2012) instead of by incision during relative sea-level fall. The observed tide to wave estuary regime change is linked to increased subsidence rates at 57 Ma that generated a higher tidal prism. As the subsidence rates slowed and the syncline broadened, the tidal prism decreased, leading to the development of more wave-dominated facies. The intervening coal seams

Probabilistic modelling and uncertainty analysis of flux and water balance changes in a regional aquifer system due to coal seam gas development.

Science.gov (United States)

Sreekanth, J; Cui, Tao; Pickett, Trevor; Rassam, David; Gilfedder, Mat; Barrett, Damian

2018-09-01

Large scale development of coal seam gas (CSG) is occurring in many sedimentary basins around the world including Australia, where commercial production of CSG has started in the Surat and Bowen basins. CSG development often involves extraction of large volumes of water that results in depressurising aquifers that overlie and/or underlie the coal seams thus perturbing their flow regimes. This can potentially impact regional aquifer systems that are used for many purposes such as irrigation, and stock and domestic water. In this study, we adopt a probabilistic approach to quantify the depressurisation of the Gunnedah coal seams and how this impacts fluxes to, and from the overlying Great Artesian Basin (GAB) Pilliga Sandstone aquifer. The proposed method is suitable when effects of a new resource development activity on the regional groundwater balance needs to be assessed and account for large scale uncertainties in the groundwater flow system and proposed activity. The results indicated that the extraction of water and gas from the coal seam could potentially induce additional fluxes from the Pilliga Sandstone to the deeper formations due to lowering pressure heads in the coal seams. The median value of the rise in the maximum flux from the Pilliga Sandstone to the deeper formations is estimated to be 85ML/year, which is considered insignificant as it forms only about 0.29% of the Long Term Annual Average Extraction Limit of 30GL/year from the groundwater management area. The probabilistic simulation of the water balance components indicates only small changes being induced by CSG development that influence interactions of the Pilliga Sandstone with the overlying and underlying formations and with the surface water courses. The current analyses that quantified the potential maximum impacts of resource developments and how they influences the regional water balance, would greatly underpin future management decisions. Copyright © 2018 Elsevier B.V. All rights

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)

无

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.

Evaluation of a Compact Coaxial Underground Coal Gasification System Inside an Artificial Coal Seam

Directory of Open Access Journals (Sweden)

Fa-qiang Su

2018-04-01

Full Text Available The Underground Coal Gasification (UCG system is a clean technology for obtaining energy from coal. The coaxial UCG system is supposed to be compact and flexible in order to adapt to complicated geological conditions caused by the existence of faults and folds in the ground. In this study, the application of a coaxial UCG system with a horizontal well is discussed, by means of an ex situ model UCG experiment in a large-scale simulated coal seam with dimensions of 550 × 600 × 2740 mm. A horizontal well with a 45-mm diameter and a 2600-mm length was used as an injection/production well. During the experiment, changes in temperature field and product gas compositions were observed when changing the outlet position of the injection pipe. It was found that the UCG reactor is unstable and expands continuously due to fracturing activity caused by coal crack initiation and extension under the influence of thermal stress. Therefore, acoustic emission (AE is considered an effective tool to monitor fracturing activities and visualize the gasification zone of coal. The results gathered from monitoring of AEs agree with the measured data of temperatures; the source location of AE was detected around the region where temperature increased. The average calorific value of the produced gas was 6.85 MJ/Nm3, and the gasification efficiency, defined as the conversion efficiency of the gasified coal to syngas, was 65.43%, in the whole experimental process. The study results suggest that the recovered coal energy from a coaxial UCG system is comparable to that of a conventional UCG system. Therefore, a coaxial UCG system may be a feasible option to utilize abandoned underground coal resources without mining.

Paradise (and Herrin) lost: Marginal depositional settings of the Herrin and Paradise coals, Western Kentucky coalfield

Energy Technology Data Exchange (ETDEWEB)

O' Keefe, J.M.K.; Shultz, M.G.; Rimmer, S.M. [University of Kentucky, Department of Earth and Environmental Sciences, Lexington, KY 40506 (United States); Hower, J.C. [University of Kentucky, Center for Applied Energy Research, 2540 Research Park Dr., Lexington, KY 40511 (United States); Popp, J.T. [Alliance Coal, Lexington, KY 40503 (United States)

2008-08-05

This is the fourth installment in a series of papers on the Asturian (Westphalian D) disrupted mire margins, termed the ''ragged edge'' in previous papers, and limestone distributions in the Herrin-Baker coal interval in the Western Kentucky extension of the Illinois Basin. New data, indicating in-situ peat development and marine influence, collected from the first in-mine exposure of this interval are presented. Borehole data from the region are examined in the context of ''ragged edge'' exposures and a carbonate platform depositional model for this portion of the Illinois Basin is presented. This shows that deposition of the sequence was influenced both by the underlying sediments and by a marine transgression. The former influence is seen in variations in coal and limestone thickness over sandstone-filled channels versus over shale bayfill deposits. The latter is marked by the progressive upwards loss of coal benches (i.e., the bottom bench of both coals is the most extensive and the Herrin coal is more extensive than the overlying Paradise coal) and by marine partings in both coals. Further, the brecciated margins seen in both coal seams are similar to brecciated peats encountered along the Everglades margins of Southwest Florida. Overall coal distributions are similar to both those along the Everglades margins and those along a transect from the Belize coast to Ambergis Caye. (author)

SULPHIDE MINERALIZATION IN UPPER WESTPHALIAN COAL SEAMS FROM THE EASTERN PART OF THE UPPER SILESIAN COAL BASIN

Directory of Open Access Journals (Sweden)

Lipiarski Ireneusz

1997-10-01

Full Text Available Morphologically diversified sulphide mineralization has been found in No. 301 and 302 coal seams (Westphalian B. The main sulphide is pyrite which forms veinlets cross-cutting the sedimentary fabrics of the coal, encrusts the cellular structures and intergrowths with oxysulphides. Two generations of pyrites were observed: the preceding and the following the oxysulphides. Pyrite composition is stoichiometric, rare admixtures are up to(in wt.%: Mn - 0.19, Co - 0.48, Ni - 0.42 and As - 1.41. Iron oxysulphides contain up to 35.06 wt.% oxygen. Their composition varies between FeS2O and FeS2O3. Increased contents of As (up to 1.46 wt.% and Pb (up to 0.96 wt.% were detected.

Characteristics of the Roof Behaviors and Mine Pressure Manifestations During the Mining of Steep Coal Seam

Science.gov (United States)

Hong-Sheng, Tu; Shi-Hao, Tu; Cun, Zhang; Lei, Zhang; Xiao-Gang, Zhang

2017-12-01

A steep seam similar simulation system was developed based on the geological conditions of a steep coal seam in the Xintie Coal Mine. Basing on similar simulation, together with theoretical analysis and field measurement, an in-depth study was conducted to characterize the fracture and stability of the roof of steep working face and calculate the width of the region backfilled with gangue in the goaf. The results showed that, as mining progressed, the immediate roof of the steep face fell upon the goaf and backfilled its lower part due to gravity. As a result, the roof in the lower part had higher stability than the roof in the upper part of the working face. The deformation and fracture of main roof mainly occurred in the upper part of the working face; the fractured main roof then formed a "voussoir beam" structure in the strata's dip direction, which was subjected to the slip- and deformation-induced instability. The stability analysis indicated that, when the dip angle increased, the rock masses had greater capacity to withstand slip-induced instability but smaller capacity to withstand deformation-induced instability. Finally, the field measurement of the forces exerted on the hydraulic supports proved the characteristics of the roof's behaviors during the mining of a steep seam.

The genesis and isotopic composition of carbonates associated with some Permian Australian coals

International Nuclear Information System (INIS)

Gould, K.W.; Smith, J.W.

1979-01-01

Siderite and calcite are the two forms of carbonate commonly associated with Permian Australian coals. The former occurs as disseminated spherulites and is a product of the early post-depositional environment. Isotopic measurements show that the CO 2 fixed as siderite did not result from the direct oxidation of photosynthetically derived materials, but rather from the anaerobic fermentation of these. The higher concentrations of calcite are generally found towards the roofs of coal seams and are characterized by isotopic enrichments to delta 13 C values of +25% PDB. Isotopic exchange between CO 2 and CH 4 within the coal seam is postulated as the mechanism which leads to the formation of isotopically heavy CO 2 . At sites along the seam margins where the CO 2 escapes, interaction with circulating metal ions or preexisting calcite results in the deposition of ''heavy'' calcite. With increasing alteration of coal by thermal metamorphism, the 13 C content of calcites and finally siderites decreases so that it more nearly approaches that of the associated coal. (Auth.)

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

Science.gov (United States)

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

2016-03-01

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 variable 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 quantify the stability factor of the supported roof of the entries at selected locations. The SRM-calculated stability 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.

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.

Vadose Zone Fate and Transport Simulation of Chemicals Associated with Coal Seam Gas Extraction

Science.gov (United States)

Simunek, J.; Mallants, D.; Jacques, D.; Van Genuchten, M.

2017-12-01

The HYDRUS-1D and HYDRUS (2D/3D) computer software packages are widely used finite element models for simulating the one-, and two- or three-dimensional movement of water, heat, and multiple solutes in variably-saturated media, respectively. While the standard HYDRUS models consider only the fate and transport of individual solutes or solutes subject to first-order degradation reactions, several specialized HYDRUS add-on modules can simulate far more complex biogeochemical processes. The objective of this presentation is to provide an overview of the HYDRUS models and their add-on modules, and to demonstrate applications of the software to the subsurface fate and transport of chemicals involved in coal seam gas extraction and water management operations. One application uses the standard HYDRUS model to evaluate the natural soil attenuation potential of hydraulic fracturing chemicals and their transformation products in case of an accidental release. By coupling the processes of retardation, first-order degradation and convective-dispersive transport of the biocide bronopol and its degradation products, we demonstrated how natural attenuation reduces initial concentrations by more than a factor of hundred in the top 5 cm of the vadose zone. A second application uses the UnsatChem module to explore the possible use of coal seam gas produced water for sustainable irrigation. Simulations with different irrigation waters (untreated, amended with surface water, and reverse osmosis treated) provided detailed results regarding chemical indicators of soil and plant health, notably SAR, EC and sodium concentrations. A third application uses the coupled HYDRUS-PHREEQC module to analyze trace metal transport involving cation exchange and surface complexation sorption reactions in the vadose zone leached with coal seam gas produced water following some accidental water release scenario. Results show that the main process responsible for trace metal migration is complexation of

Selective coal mining of intercalated lignite deposits

Energy Technology Data Exchange (ETDEWEB)

Zunic, R [Kolubara-Projekt, Lazarevac (Yugoslavia)

1991-01-01

Describes selective coal mining in the Tamnava-Istocno Polje coal surface coal mine (Yugoslavia), designed for an annual coal production of 11.4 Mt. Until 1991, this mine exploited one thick lignite seam, without spoil intercalations, using a bucket wheel excavator-conveyor-spreader system both for coal mining and removal of overburden. In the future, several spoil intercalations of up to 1.0 m and thicker will appear with a total volume of 22 million m{sup 3}. These intercalations have to be selectively excavated in order to guarantee the calorific value of coal for the Nikola Tesla power plant. Computer calculations were carried out to determine the decrease in excavator coal production due to selective mining of spoil strata. Calculations found that the annual surface mine capacity will be lower by at most 9%, depending on thickness of spoil intercalations. The useful operation time of excavators will be reduced by 98 hours per year. The planned annual coal production will nevertheless be fulfilled. 3 refs.

近距离煤层群上行开采研究%Study on ascending mining of close distance coal seams group

Institute of Scientific and Technical Information of China (English)

庞冬冬

2017-01-01

为研究8煤开采对上部11煤的影响,综合运用理论分析和数值计算的方法,对上行开采过程中,上部11煤底板位移场.应力场变化规律进行研究.结果表明:11煤位于8煤开采的弯曲下沉带内,煤体有一定的破坏,但保持了很好的连续性,而且14128工作面的开采降低了上煤层的应力,形成应力降低区;同时,增大了11煤的透气性,减小瓦斯压力,卸压效果显著,对高瓦斯的11煤安全开采提供了保障.最后,计算得出了卸压影响范围.%In order to study the influence of No.8 seam mining on the upper No.11 seam,theoretical analysis and numerical calculation were used to study the change law of the displacement field and stress field of the upper No.11 seam floor during ascending mining.The results show that No.11 seam is located in the curve subsidence zone of No.8 seam mining,the coal body has certain damage,but it has a good continuity,and the stress of the upper coal seam is reduced because of the mining of 14128 working face and the stress decreasing zone has formed;at the same time,the permeability of No.11 coal increases,the gas pressure reduces,and pressure-relaxing effect is obvious,and it provides protection for the safe mining of No.11 seam which is of high gas.At last,the influence range of pressure relief is calculated.

Study on Resources Assessment of Coal Seams covered by Long-Distance Oil & Gas Pipelines

Science.gov (United States)

Han, Bing; Fu, Qiang; Pan, Wei; Hou, Hanfang

2018-01-01

The assessment of mineral resources covered by construction projects plays an important role in reducing the overlaying of important mineral resources and ensuring the smooth implementation of construction projects. To take a planned long-distance gas pipeline as an example, the assessment method and principles for coal resources covered by linear projects are introduced. The areas covered by multiple coal seams are determined according to the linear projection method, and the resources covered by pipelines directly and indirectly are estimated by using area segmentation method on the basis of original blocks. The research results can provide references for route optimization of projects and compensation for mining right..

Use of neutron activation analysis to measure the variation in trace element concentrations in a coal seam

International Nuclear Information System (INIS)

Fardy, J.J.; Swaine, D.J.

1985-01-01

Trace element concentrations were measured by neutron activation on 57 run-of-mine coal samples from several locations in seven mines located in the Lithgow seam in the Western Coalfield, Sydney Basin. Results were tabulated as ratios of the highest to the lowest variance for each element

A fluvioglacial and gaciolacustrine deltaic depositional model for Permo-Carboniferous coals of the northeastern Karoo Basin, South Africa

Energy Technology Data Exchange (ETDEWEB)

Smith G, Le Blanc; Eriksson, K A

1979-01-01

With the northward retreat of the late Palaeozoic Gondwana ice sheet a series of glacial valleys, partially filled with diamictite, dominated the landscape along the northern edge of the Karoo basin in South Africa. Consequent outwash sediments accumulated as fluvioglacial and glaciolacustrine deltaic deposits. Density underflow generated turbidity currents from which bottomset sediments were deposited. These comprise distal varved siltstones and shales, stratified pebbly-mudstone with dropstones, and proximal ripple drift cross-laminated sandstones and siltstones. Overlying outwash plain conglomerates and sandstones constitute the topset deposits. Upon abandonment of the outwash plain, shallow-rooted Arctic vegetation developed. Resulting peats exceeded 10 m in thickness and constituted precursors to coal seams in which variations in ash content are attributed to overbank splaying from recognisable anastomosing channels within the coal swamps. This study has illustrated a characteristic paraglacial sedimentation sequence, maximum depositional rates occur immediately after glacial retreat followed by decelerating sedimentation rates through time, leading finally to the development of extensive peats. (29 refs.)

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.)

Coal plows in underground mines in Czechoslovakia

Energy Technology Data Exchange (ETDEWEB)

Vasek, J.; Klimek, M.

1980-05-01

This article discusses factors which influence the possibility of using coal plows for mining black coal seams in Czechoslovakia. Seams inclined at angles up to 40 degrees can be mined by plows. Another factor which influences plow work is ease of separating coal seam from the direct roof: the plow can be used in seams with good or average separation, and can not be used in seams with roofs difficult to separate from the seam. Quality of rocks surrounding the coal seam: If the stability of the roof is low and strength of rock is low and roof falls occur easily coal plows can not be used. From among three classes of rock in Czechoslovakia plows can be used only in the class characterized by the highest strength. Intense seam dislocations are one of the most important difficulties in using coal plows. Plows can be used if height of seam dislocations is not greater than 40% of the seam thickness. Further factors which influence the possibility of using coal plows (coal resistance to cutting, features of cutting elements of the plow, specific features of the plow mechanism etc.) are also discussed. A method for assessing advantages and disadvantages of using coal plows in given circumstances is presented. (10 refs.) (In Czech)

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)

In-seam seismic surveys at Polio and Santiago collieries during the month of January

Energy Technology Data Exchange (ETDEWEB)

1987-01-01

In-seam seismic surveys were carried out over the last two weekends in January in order to assess two coal panels, one in seam Cuatro at Polio colliery between levels 4 and 5 of the Centella field and the other in the Mariana seam at Santiago colliery between levels 3,5, and 7 in the Desquite zone. Geological research called in-seam seismics, which is just being developed in Spain, is a geophysical method developed specially for detailed investigation of coal seams.

Petrography and rank of the Bhangtar coals, southeastern Bhutan

Energy Technology Data Exchange (ETDEWEB)

Pareek, H S [BH23, Meerut (India)

1990-07-01

In Bhutan, a potential coal deposit is exposed at Bhangtar in the 'landslide zone'. Nineteen coal seams are encountered in this area, and occur in the Lower Gondwana Supergroup preserved in between the Main Boundary Fault and the Thrust. The coal is low in moisture, {lt}1.76%, but the coal cores show moisture values of 3.16%. The ash content is up to 48.87% and increases substantially in the younger seams. The volatile content (on a pure coal basis) ranges from 23.38% to 41.02%. The sulphur content is less than 0.61%. The coals are non-coking. The amount of trace elements in the coal is quite low. The average petrographic composition of the Bhangtar coal is vitrinite - 31%, exinite - 2%, inertinite - 31%, and mineral and shaly matter - 36%, the vitrinite proportion decreases from the older to the younger seams, which are shaly. an age can be assigned to the Bhangtar coal. Based on oil reflectance, the rank of the coal is metalignitous to hypobituminous. The average microlithotype composition of the coal is vitrite - 30%, clarite - 1%, vitrinertite V - 14%, vitrinertite I - 11%, durite - 3%, fusite - 14%, and carbominerite - 27%. Vitrite decreases in proportion towards the younger seams, 'intermediates' show a concomitant increase, while durite and fusite remain constant. Carbonaceous shale contains fragmentary inertinite and vitrinite macerals and is interlayered with micro-bands of shaly coal which is characterised by abundant fragments of fusinite and vitrinite. The coal is very fragile and thus amenable to economic beneficiation. The coal is used as fuel in electric power plants. The Bhangtar coal is characteristically distinct from the Gondwana coals of India in petrography and rank, but correlates petrographically with the Kameng coals of Arunachal Pradesh, India. 18 refs., 4 figs., 8 tabs., 3 plates.

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.

Geology and coal potential of Somaliland

Energy Technology Data Exchange (ETDEWEB)

M.Y. Ali [Petroleum Institute, Abu Dhabi (United Arab Emirates)

2009-07-01

Geological field mapping along with available geological and drilling data suggest that Somaliland (Northwestern Somalia) has favourable stratigraphy and structure for coal deposits. Lignitic to sub-bituminous coal deposits with ages from Jurassic to Oligocene-Miocene occur in various locations across the country including Hed-Hed valley south of Onkhor, Guveneh hills north of Las Dureh and Daban Basin southeast of Berbera. However, the coal occurrence at Hed-Hed has both the greatest thickness and highest quality. These deposits have the potential to provide an important alternative fuel resource which could alleviate the growing shortage of traditional fuels and assist in reducing the country's dependence on imported energy. However, further investigation, including drilling and laboratory analyses, still needs to be carried out, particularly on the Upper Cretaceous coal seams to evaluate the quality and resource potential of the deposits.

Gondwana basins and their coal resources in Bangladesh

International Nuclear Information System (INIS)

Nehaluddin, M.; Sultan-ul-Islam, M.

1994-01-01

Fault bounded five Gondwana basins have been discovered in the north western Bangladesh. Among these basins show considerable amount of coal deposits. The Gondwana rocks are highly formed during the Permo-carboniferous diastrophism and later on acquired dynamic characters. In almost all basins, the Permian rocks overlie the Precambrian basement and underlie either the Tertiary or the Cretaceous sediments, structural, stratigraphic, and depositional history of these basins is more or less similar. The sedimentary sequences are composed of light to dark gray, fine to very coarse grained, sub angular to sub rounded felspathic sandstone, dark grey carbonaceous shale and sandstone, variegated conglomerate and thick coal seams (single seam max. 42.38m). The rocks are often alternated and bear the characteristics of cyclic sedimentation. The depositional environments varied from restricted drainage to open fluvial dominated low to moderate sinuous drainage system. The coal bearing basins were flanked by vegetated and swampy over bank. Age of these coals is suggested to be the late permian. Proved and probable reserves of coal in Jamalganj-Paharpur basin are 670 and 1,460 million metric tons, in Barapukuria basin 303 and 3899 million metric tons; in Barapukuria basin 303 and 389 million metric tons; and in Khalaspir basin 143 and 685 million metric tons respectively. The coal is high volatile, low sulphur, bituminous type. It can be used for different forms of thermal conversion. (author)

Environmental impact of coal mining and coal seam gas production on surface water quality in the Sydney basin, Australia.

Science.gov (United States)

Ali, A; Strezov, V; Davies, P; Wright, I

2017-08-01

The extraction of coal and coal seam gas (CSG) will generate produced water that, if not adequately treated, will pollute surface and groundwater systems. In Australia, the discharge of produced water from coal mining and related activities is regulated by the state environment agency through a pollution licence. This licence sets the discharge limits for a range of analytes to protect the environment into which the produced water is discharged. This study reports on the impact of produced water from coal mine activities located within or discharging into high conservation environments, such as National Parks, in the outer region of Sydney, Australia. The water samples upstream and downstream from the discharge points from six mines were taken, and 110 parameters were tested. The results were assessed against a water quality index (WQI) which accounts for pH, turbidity, dissolved oxygen, biochemical oxygen demand, total dissolved solids, total phosphorus, nitrate nitrogen and E .coli. The water quality assessment based on the trace metal contents against various national maximum admissible concentration (MAC) and their corresponding environmental impacts was also included in the study which also established a base value of water quality for further study. The study revealed that impacted water downstream of the mine discharge points contained higher metal content than the upstream reference locations. In many cases, the downstream water was above the Australia and New Zealand Environment Conservation Council and international water quality guidelines for freshwater stream. The major outliers to the guidelines were aluminium (Al), iron (Fe), manganese (Mn), nickel (Ni) and zinc (Zn). The WQI of surface water at and downstream of the discharge point was lower when compared to upstream or reference conditions in the majority of cases. Toxicology indices of metals present in industrial discharges were used as an additional tool to assess water quality, and the newly

Determining the hydraulic and fracture properties of the Coal Seam Gas well by numerical modelling and GLUE analysis

Science.gov (United States)

Askarimarnani, Sara; Willgoose, Garry; Fityus, Stephen

2017-04-01

Coal seam gas (CSG) is a form of natural gas that occurs in some coal seams. Coal seams have natural fractures with dual-porosity systems and low permeability. In the CSG industry, hydraulic fracturing is applied to increase the permeability and extract the gas more efficiently from the coal seam. The industry claims that it can design fracking patterns. Whether this is true or not, the public (and regulators) requires assurance that once a well has been fracked that the fracking has occurred according to plan and that the fracked well is safe. Thus defensible post-fracking testing methodologies for gas generating wells are required. In 2009 a fracked well HB02, owned by AGL, near Broke, NSW, Australia was subjected to "traditional" water pump-testing as part of this assurance process. Interpretation with well Type Curves and simple single phase (i.e. only water, no gas) highlighted deficiencies in traditional water well approaches with a systemic deviation from the qualitative characteristic of well drawdown curves (e.g. concavity versus convexity of drawdown with time). Accordingly a multiphase (i.e. water and methane) model of the well was developed and compared with the observed data. This paper will discuss the results of this multiphase testing using the TOUGH2 model and its EOS7C constitutive model. A key objective was to test a methodology, based on GLUE monte-carlo calibration technique, to calibrate the characteristics of the frack using the well test drawdown curve. GLUE involves a sensitivity analysis of how changes in the fracture properties change the well hydraulics through and analysis of the drawdown curve and changes in the cone of depression. This was undertaken by changing the native coal, fracture, and gas parameters to see how changing those parameters changed the match between simulations and the observed well drawdown. Results from the GLUE analysis show how much information is contained in the well drawdown curve for estimating field scale

Analysis of anomalous high concentration of lead and selenium and their origin in the main minable coal seam in the Junger coalfield

Energy Technology Data Exchange (ETDEWEB)

Li Sheng-sheng; Ren De-yi [State Administration of Work Safety, Beijing (China)

2006-07-01

The concentration, occurrence, and geological origin of lead and selenium in the main minable coal seam from the Junger coalfield were studied using inductively coupled plasma mass spectrometry (CICP-MS), instrumental neutron activation analysis (CINAA), scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (SEM-EDX), and optical microscope. The results show that the average concentrations of Pb and Se are as high as 35.7 {mu}g/g and 8.2 {mu}g/g, respectively, which are much higher than those of coals from North China, Guizhou, China, and USA. In addition, their enrichment factors are up to 2.4 and 68.1, respectively. Lead and selenium are significantly enriched in the seam. Lead and selenium mainly exist in galena, clausthalite, and selenio-galena which occur as cell-filling of coal-forming plants and are of chemical-sedimentary origin. 22 refs., 3 figs., 1 tab.

Petrographic characteristics and depositional environment of Miocene Can coals, Canakkale-Turkey

Energy Technology Data Exchange (ETDEWEB)

Guerdal, Guelbin; Bozcu, Mustafa [Canakkale Onsekiz Mart University, Engineering and Architecture Faculty (Turkey)

2011-01-01

In this study, petrographic examinations along with proximate, calorific value, ultimate, sulphur form and XRD analyses were performed in order to determine the coal characteristics and the depositional environment of the Miocene Can coals. Seventy coal samples were taken from cores and open pit mines. The investigated Can coals are humic coals and classified as lignite to sub-bituminous coal based on the random huminite reflectance (0.38-0.54% R{sub r}), volatile matter (45.50-62.25 wt.%, daf) and calorific value (3419-6479 kcal/kg, maf). The sulphur content of the Can coals changes from 0.30 up to 12.23 wt.%, and a broad range of ash contents was observed varying between 2.46 wt.% and 41.19 wt.%. Huminite is the most abundant maceral group (74-95 vol.% mmf) consisting of mostly humocollinite (gelinite) which is followed by relatively low liptinite (2-18 vol.% mmf) and inertinite content (2-13 vol.% mmf). In general, major mineral contents of coal samples are clay minerals, quartz, mica, pyrite and feldspar. The Can-Etili lignite basin consists of mainly volcano-clastics, fluviatile and lacustrine clastic sediments and contains only one lignite seam with 17 m average thickness. In order to assess the development of paleo-mires, coal facies diagrams were obtained from maceral composition. According to the Vegetation Index (VI) and Ground Water Index (GWI), the Can coal accumulated in inundated marsh, limnic and swamp environments under a rheotrophic hydrological regime. In general, the facies interpretations are in accordance with the observed sedimentalogical data. (author)

Investigation of subsidence event over multiple seam mining area

International Nuclear Information System (INIS)

Kohli, K.K.

1999-01-01

An investigation was performed to determine the sequence of events which caused the 1987 surface subsidence and related damage to several homes in Walker County, Alabama, USA. Surface affects compared to mine maps indicated the subsidence to be mine related. However, two coal seams had been worked under this area. The upper seam, the American seam, ranged from 250 to 280 feet beneath the surface in the area in question. It was mined-out before 1955 by room-and-pillar method leaving in place narrow-long pillars to support the overburden strata, and abandoned in 1955. The lower seam, the Mary Lee seam, ranged from 650 to 700 feet beneath the surface. The Mary Lee seam had been abandoned in 1966 and subsequently became flooded. The dewatering of the Mary Lee seam workings in 1985 caused the submerged pillars to be exposed to the atmosphere. Due to multiple seam mining and the fact that workings had been inundated then dewatered, a subsurface investigation ensued to determine the sequence and ultimate cause of surface subsidence. Core sample tests with fracture analysis in conjunction with down-the-hole TV camera inspections provided necessary information to determine that the subsidence started in the lower seam and progressed through the upper coal seam to the surface. Evidence from the investigation program established that dewatering of the lower seam workings caused the marginally stable support pillars and the roof to collapse. This failure triggered additional subsidence in the upper seam which broadened the area of influence at the surface

A New Tree-Type Fracturing Method for Stimulating Coal Seam Gas Reservoirs

Directory of Open Access Journals (Sweden)

Qian Li

2017-09-01

Full Text Available Hydraulic fracturing is used widely to stimulate coalbed methane production in coal mines. However, some factors associated with conventional hydraulic fracturing, such as the simple morphology of the fractures it generates and inhomogeneous stress relief, limit its scope of application in coal mines. These problems mean that gas extraction efficiency is low. Conventional fracturing may leave hidden pockets of gas, which will be safety hazards for subsequent coal mining operations. Based on a new drilling technique applicable to drilling boreholes in coal seams, this paper proposes a tree-type fracturing technique for stimulating reservoir volumes. Tree-type fracturing simulation experiments using a large-scale triaxial testing apparatus were conducted in the laboratory. In contrast to the single hole drilled for conventional hydraulic fracturing, the tree-type sub-boreholes induce radial and tangential fractures that form complex fracture networks. These fracture networks can eliminate the “blank area” that may host dangerous gas pockets. Gas seepage in tree-type fractures was analyzed, and gas seepage tests after tree-type fracturing showed that permeability was greatly enhanced. The equipment developed for tree-type fracturing was tested in the Fengchun underground coal mine in China. After implementing tree-type fracturing, the gas extraction rate was around 2.3 times greater than that for traditional fracturing, and the extraction rate remained high for a long time during a 30-day test. This shortened the gas drainage time and improved gas extraction efficiency.

Fiscal 1998 overseas geological structure survey. Japan-China joint coal survey Mei-Xian project; 1998 nendo kaigai chishitsu kozo nado chosa hokokusho. Nippon Chugoku sekitan kyodo tansa Mei-Xian project

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

Japan-China joint coal survey was made through seismic prospecting by Japanese group and drilling prospecting by Chinese group. Mei-Xian mine property includes coal seams of the Jurassic period, and is covered with the quaternary period stratum without any coal seam. The base of the quaternary period stratum exists at depth of 50-400m, while the coal seams at depth of 300-700m. Among 11 existing seams, the 1st and 5th seams are main objects for prospecting. The 5th seam of 0.2-8.96m (2.95m in average) thick is the most expected important one, distributing all over the mine property. The 5th seam also has branch seams spreading over 2.5km from east to west and 1.2km from south to north in the center part of the mine property. The 1st seam of 0-8.62m (2.90m in average) thick is most thick in the south part of the mine property. The theoretical amount of coal deposits in the whole coal seam is estimated to be nearly 290,000,000t by Chinese group (nearly 50% of it in the 5th seam). That is also estimated to be nearly 346,000,000t by Japanese group (155,000,000t in the 5th seam). Both 1st and 5th seams are composed of sub-bituminous coal. (NEDO)

A Gas–Solid–Liquid Coupling Model of Coal Seams and the Optimization of Gas Drainage Boreholes

Directory of Open Access Journals (Sweden)

Yuexia Chen

2018-03-01

Full Text Available For a gas–solid–liquid coupling model of coal seams, previous permeability models basically supposed uniaxial strains as the boundary condition for coal reservoirs without considering the deformation caused by changes in humidity. The permeability model varies under different boundary conditions. According to the true triaxial stress state of coal reservoirs, a permeability model considering the effective stress, sorption and desorption, and wet strain was established. Based on the permeability model, the continuity equation of gas and water and the stress field equation were coupled. Then, the model was incorporated in the COMSOL suite to simulate gas drainage from boreholes in floor roadways passing through seams in a coal mine. By comparing with the measured gas flow on site, the model was verified as being reliable. Moreover, the spacing and layout shape of boreholes in floor roadways were simulated. To achieve the aim of eliminating regional outburst within 180 days and decreasing the number of boreholes so as to reduce the cost, the spacing and shape of boreholes were optimized. When the superimposed effect of the boreholes was not considered, the optimal spacing of boreholes was 3 r; if the superimposed effect was taken into account, the spacing could be set to within 3 r ≤ L ≤ R, where r and R represent the effective gas drainage radius and the influence radius of gas drainage, respectively. The borehole spacing could be appropriately increased when the boreholes were arranged in rhomboidal form. To achieve the same range of outburst elimination, the rhomboidal layout can decrease the number of boreholes to reduce cost, thus realizing the objective of this optimization process.

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.

Source and Enrichment of Toxic Elements in Coal Seams around Mafic Intrusions: Constraints from Pyrites in the Yuandian Coal Mine in Anhui, Eastern China

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Yanfei An

2018-04-01

Full Text Available Pyrite, a mineral that can cause potential environmental issues in coal mining, is commonly found in coal seams around intrusions. In this paper, pyrites from the Yuandian Coal Mine (Huaibei Coalfield, Anhui, Eastern China were studied using SEM, Raman and LA-ICP-MS. The pyrite morphologic and geochemical data suggest that (1 four pyrite generations are present (framboidal sedimentary pyrites (Py I in the original coal, coarse-grained magmatic pyrites (Py II in the intruding diabase, fine-grained metamorphic pyrites (Py III in the intrusive contact aureole, and spheroid/vein hydrothermal pyrites (Py IV in the cokeite; and (2 concentrations of cobalt, nickel, arsenic, selenium, lead and copper in the metamorphic pyrites are much higher than the other pyrite generations. We propose that mafic magmatism is the main contributor of the toxic elements to the intrusion-related cokeite at Yuandian.

Technique for reinforcing development working in lower strata of thick coal seams

Energy Technology Data Exchange (ETDEWEB)

Andranovich, V A; Gromov, Yu V; Kurglikov, V P

1981-01-15

This device is to be used by mining industry, specifically for reinforcing development work in bottom strata of thick coal seams having a layer depression. Reinforcing consists of drilling a hole, or making cutting slits and lowering support props for the stratum below through them, as well as lowering the roof timber on the ground. To cut back expenditures on installation and removal of equipment, drilling or making cutting slits is done to a depth equal to the total height of the substrata, and the support props are laid for all of the substrata. Only the roof timber is lowered on the ground during work on the layers.

Improved coal winning in Zollverein 7/8 seam by toe-in plough 9. 30 v supplied by GEW Luenen

Energy Technology Data Exchange (ETDEWEB)

Schwolow, G; Dornack, M; Plich, H

1982-04-01

The project aimed at mining Zollverein 7/8 seam more efficiently than with drag-hook ploughs. Zollverein 7/8 seam is characterized by mechanically tough coal changing, seam thickness, a somewhat 'corrugated' shape, and a soft floor. Comparative investigations on one toe-in plough face and one drag-hook plough face in two neighbouring panels of said seam were made for individual plough travels as well as over several months of operation. These investigations were backed up by measuring. The measuring conditions were identical in both panels. The face equipments were identical except for the plough systems. The energy pick-up relative to the web is by 43% lower with the toe-in plough compared to the drag-hook plough. As to wear, for the toe-in plough in comparison to the drag-hook plough twice the longevity of the latter was recorded. For the noise level on the plough guides only marginal difference in favor to the toe-in plough could be recorded. Analyses of dust and particle-size distribution showed no obvious advantages for either of both plough systems.

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.

Geochemistry of trace elements in coals from the Zhuji Mine, Huainan Coalfield, Anhui, China

Science.gov (United States)

Sun, R.; Liu, Gaisheng; Zheng, Lingyun; Chou, C.-L.

2010-01-01

The abundances of nine major elements and thirty-eight trace elements in 520 samples of low sulfur coals from the Zhuji Mine, Huainan Coalfield, Anhui, China, were determined. Samples were mainly collected from 10 minable coal seams of 29 boreholes during exploration. The B content in coals shows that the influence of brackish water decreased toward the top of coal seams; marine transgression and regression occurred frequently in the Lower Shihezi Formation. A wide range of elemental abundances is found. Weighted means of Na, K, Fe, P, Be, B, Co, Ni, Cr, Se, Sb, Ba, and Bi abundances in Zhuji coals are higher, and the remainder elements are either lower or equal to the average values of elements in coals of northern China. Compared to the Chinese coals, the Zhuji coals are higher in Na, K, Be, B, Cr, Co, Se, Sn, Sb, and Bi, but lower in Ti, P, Li, V and Zn. The Zhuji coals are lower only in S, P, V and Zn than average U.S. and world coals. Potassium, Mg, Ca, Mn, Sr, As, Se, Sb and light rare earth elements (LREE) had a tendency to be enriched in thicker coal seams, whereas Fe, Ti, P, V, Co, Ni, Y, Mo, Pb and heavy rare earth elements (HREE) were inclined to concentrate in thinner coal seams. The enrichment of some elements in the Shanxi or Upper Shihezi Formations is related to their depositional environments. The elements are classified into three groups based on their stratigraphic distributions from coal seams 3 to 11-2, and the characteristics of each group are discussed. Lateral distributions of selected elements are also investigated. The correlation coefficients of elemental abundances with ash content show that the elements may be classified into four groups related to modes of occurrence of these elements. ?? 2009 Elsevier B.V. All rights reserved.

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.

SHRIMP zircon U–Pb ages from coal beds across the Permian–Triassic boundary, eastern Yunnan, southwestern China

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Juan Wang

2018-04-01

Full Text Available The first SHRIMP zircon U–Pb ages from coal beds close to the end-Permian mass extinction are reported from the C1 coal seam in the Yantang Mine in Laibin Town, Xuanwei County, eastern Yunnan Province. Zircons were extracted from kaolinite claystone layers, defined as tonsteins (volcanic ash deposits, in the sub-seam B1 and B3 of the coal seam C1. The U–Pb ages are 252.0 ± 2.3 Ma and 250.3 ± 2.1 Ma for the sub-seam B1 and B3, respectively. Within analytical uncertainties, these U–Pb ages include the time period of the onset of the mass extinction at 251.941 ± 0.037 Ma, which was obtained from the marine Meishan section in Zhejiang Province, ∼1600 km away from the Yantang Mine. These new ages represent not only the first and closest ages to the PTB mass extinction in terrestrial coal beds, but also ages from the nearest site to the Emeishan volcanoes investigated so far. Therefore these new data provide the most accurate stratigraphic horizon of terrestrial facies of the end-Permian extinction in South China. The Emeishan volcanoes were likely the source of volcanic ash in the coal seams at the Xuanwei County and broader areas in South China. Furthermore, the minerals and geochemistry characteristics of the C1 coal seam also implied the influences of contemporaneous volcanic activities. Keywords: PTB mass extinction, C1 coal seam, SHRIMP U–Pb isotope age, Xuanwei County, Yunnan Province

Mineralogical and geochemical characterization of the Jurassic coal from Egypt

Energy Technology Data Exchange (ETDEWEB)

Baioumy, H.M. [Central Metallurgical Research and Development Institute, Cairo (Egypt)

2009-06-15

The Jurassic coal deposit in the Maghara area, Sinai, Egypt contains at least 11 coal seams of lenticular shape. The thickness of the main coal seams ranges from 130 cm to 2 m and are underlain and overlain by thin black shale beds. Mineralogical analysis indicated that this coal is characterized by low mineral matter with traces of quartz in some samples. However, coal ash is made up of quartz with traces of calcite, anhydrite, and hematite. Analysis of coal rank parameters indicated that the Maghara coal can be classified as medium volatile bituminous coal. The high sulfur contents and the relatively high proportion of pyritic sulfur suggest a possible marine transgression after the deposition of precursor peat. This interpretation is supported by the relatively high B contents. The relatively high Ge in the Maghara coal could be attributed to an infiltration of Ge enriched water from the surrounding siliceous sediments probably during diagenesis. The high Au contents were contributed to an Au-rich provenance of the ash contents of this coal. Rare earth elements geochemistry indicated low concentrations of these elements with slight enrichment of light rare earth elements (LREEs), slight negative Eu anomaly, and relatively flat heavy rare earth elements (HREEs) patterns. The low contents of trace and rare earth elements, particularly those with environmental relevance, compared to the usual concentration ranges in worldwide coal gives an advantage for this coal.

Coal seam gas-supply and impact on U.S. markets and Canadian producers

International Nuclear Information System (INIS)

Kelafant, J.

1992-01-01

The basic ways in which coalbed methane differs from natural gas are described. Coalbed methane is stored at a higher capacity in the coal seam, has a different production curve, and exploration costs are lower. Comparing a conventional gas well having 2 billion ft 3 reserves with coalbed methane wells in the San Juan and Warrior basins, gas from the conventional well costs $1.90 per 1,000 ft 3 and methane from the San Juan and Warrior wells costs $1.50 and $2.40 per 1,000 ft 3 respectively. A 90 cent per 1,000 ft 3 tax credit on coalbed methane reduces the two latter costs significantly and is without doubt the driving force behind the coalbed methane industry in some areas. Examples from the Warrior and San Juan basins are described to illustrate the technology driven economics of coalbed methane. Substantial improvements in gas production can be achieved by such means as multiple seam completion technologies, improved well stimulation, optimum well spacing, and the use of cavitation completion. Technically recoverable coalbed methane resources in the USA are estimated at 145 trillion ft 3 , concentrated in the western coal basins. At a wellhead price of $2 per 1,000 ft 3 , the economically recoverable potential is ca 13 trillion ft 3 . Examining future production potential, by developing new technologies or bringing more basins on stream, production could be increased to ca 3 billion ft 3 /d in the late 1990s. It is suggested that the increased volumes of coalbed methane have had minimal impact on gas prices. 9 figs., 12 tabs

Depositional environment of the San Miguel lignite deposit in Atascosa and McMullen Counties, Texas

Energy Technology Data Exchange (ETDEWEB)

Gowan, S.W.

1985-01-01

An analysis of the environment of deposition of the San Miguel lignite deposit was carried out in order to understand newly discovered characteristics of the deposit. The environment of deposition of the overburden and underburden was evaluated through an interpretation of three continuous cores. Four coal cores and a highwall section were carefully described to determine the depositional environmental of the coal seams and partings. These studies were supplemented by the construction of seam and parting isopachs, and the analysis of the distribution of sulfur isotopes, sulfur, forms, and total sulfur within the coal. The sedimentary package is composed of a basal prograding barrier that beach, dune, and back-barrier sands. This unit correlates with a downdip sand that was also interpreted as a prograding barrier by other authors. The barrier is overlain by a series of slit and clay deposits of lagoonal, tidal flat, and tidal channel origin. These deposits are capped by restricted lagoon sediments composed of green, calcareous clays that occasionally contain shell layers. The restricted lagoon deposits formed when the barrier closed the lagoon off from the sea. Peat forming freshwater swamps eventually became established behind the barrier and on top of the restricted lagoon sediments. The parting isopachs reveal a reticulate morphology similar to the mangrove swamps located lateral to the modern Niger River Delta. The partings represent vegetated tidal flat deposits that formed during periodic invasions by the sea that killed the swamp and inundated the peat with sulfate rich water. The lignite interval is capped by open lagoon and tidal flat sediments.

Simulating the Fate and Transport of Coal Seam Gas Chemicals in Variably-Saturated Soils Using HYDRUS

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Dirk Mallants

2017-05-01

Full Text Available The HYDRUS-1D and HYDRUS (2D/3D computer software packages are widely used finite element models for simulating the one-, and two- or three-dimensional movement of water, heat, and multiple solutes in variably-saturated media, respectively. While the standard HYDRUS models consider only the fate and transport of individual solutes or solutes subject to first-order degradation reactions, several specialized HYDRUS add-on modules can simulate far more complex biogeochemical processes. The objective of this paper is to provide a brief overview of the HYDRUS models and their add-on modules, and to demonstrate possible applications of the software to the subsurface fate and transport of chemicals involved in coal seam gas extraction and water management operations. One application uses the standard HYDRUS model to evaluate the natural soil attenuation potential of hydraulic fracturing chemicals and their transformation products in case of an accidental release. By coupling the processes of retardation, first-order degradation and convective-dispersive transport of the biocide bronopol and its degradation products, we demonstrated how natural attenuation reduces initial concentrations by more than a factor of hundred in the top 5 cm of the soil. A second application uses the UnsatChem module to explore the possible use of coal seam gas produced water for sustainable irrigation. Simulations with different irrigation waters (untreated, amended with surface water, and reverse osmosis treated provided detailed results regarding chemical indicators of soil and plant health, notably SAR, EC and sodium concentrations. A third application uses the HP1 module to analyze trace metal transport involving cation exchange and surface complexation sorption reactions in a soil leached with coal seam gas produced water following some accidental water release scenario. Results show that the main process responsible for trace metal migration in soil is complexation of

Bioregional Assessments: Determining the Impacts of Coal Resource Development on Water Resources in Australia through Groundwater, Surface Water and Ecological Modelling

Science.gov (United States)

Peeters, L. J.; Post, D. A.; Crosbie, R.; Holland, K.

2017-12-01

While extraction of methane from shale gas deposits has been the principal source of the recent expansion of the industry in the United States, 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. The Australian Federal Government commissioned a multi-disciplinary programme of bioregional assessments to improve understanding of the potential impacts of coal seam gas and large coal mining activities on water resources and water-dependent assets across six bioregions Australia. A bioregional assessment is a transparent 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. The first step in the analysis is to establish the most likely scenario for coal development in each region and establish a causal pathway linking coal development to impacts to the social, economic and ecological functioning of water resources. This forms the basis for a sequence of probabilistic geological, hydrogeological, hydrological and ecological models to quantify the probability of potential impacts. This suite of models is developed independent of the proponents and regulators of coal resource developments and so can provide unbiased information to all stakeholders. To demonstrate transparency of the modelling, all inputs, outputs and executables will be available from http://www.bioregionalassessments.gov.au. The analysis delineated a zone of potential hydrological change for each region, outside of which impacts

Effects of increased rock strata stresses on coal gettability

Energy Technology Data Exchange (ETDEWEB)

Sikora, W; Skoczynski, W [Politechnika Slaska, Gliwice (Poland). Instytut Mechanizacji Gornictwa

1988-01-01

Analyzes effects of rock strata pressure on a coal seam, its cracking and on energy consumption of coal cutting by shearer loaders and coal plows. Effects of mining depth on stresses in a coal seam rib side were analyzed using formulae developed by Budryk, Chudek and Borecki. Formulae used for selecting optimum yield strength of powered supports at working faces are reviewed. Four types of spontaneous separation of coal seam blocks caused by rock strata stresses are evaluated: layers parallel to the face with constant thickness, coal blocks with thickness decreasing in the direction of the floor or roof (blocks with a planar triangle cross-cut), blocks situated in the seam layer adjacent to the floor or roof. Causes of each type of coal seam separation are analyzed. 9 refs.

Dips, ramps, and rolls- Evidence for paleotopographic and syn-depositional fault control on the Western Kentucky No. 4 coal bed, tradewater formation (Bolsovian) Illinois Basin

Science.gov (United States)

Greb, S.F.; Eble, C.F.; Williams, D.A.; Nelson, W.J.

2001-01-01

The Western Kentucky No. 4 coal is a high-volatile B to high-volatile C bituminous coal that has been heavily mined along the southern margin of the Western Kentucky Coal Field. The seam has a reputation for rolling floor elevation. Elongate trends of floor depressions are referred to as "dips" and "rolls" by miners. Some are relatively narrow and straight to slightly curvilinear in plan view, with generally symmetric to slightly asymmetric cross-sections. Others are broader and asymmetric in section, with sharp dips on one limb and gradual, ramp-like dips on the other. Some limbs change laterally from gradual dip, to sharp dip, to offset of the coal. Lateral changes in the rate of floor elevation dip are often associated with changes in coal thickness, and in underground mines, changes in floor elevation are sometimes associated with roof falls and haulage problems. In order to test if coal thickness changes within floor depressions were associated with changes in palynology, petrography and coal quality, the coal was sampled at a surface mine across a broad. ramp-like depression that showed down-dip coal thickening. Increment samples of coal from a thick (150 cm), down-ramp and thinner (127 cm), up-ramp position at one surface mine correlate well between sample sites (a distance of 60 m) except for a single increment. The anomalous increment (31 cm) in the lower-middle part of the thick coal bed contained 20% more Lycospora orbicula spores. The rolling floor elevations noted in the study mines are inferred to have been formed as a result of pre-peat paleotopographic depressions, syn-depositional faulting, fault-controlled pre-peat paleotopography, and from compaction beneath post-depositional channels and slumps. Although the association of thick coal with linear trends and inferred faults has been used in other basins to infer syn-depositional faulting, changes in palynology within increment samples of the seam along a structural ramp in this study provide

The determination of methane resources from liquidated coal mines

Science.gov (United States)

Trenczek, Stanisław

2017-11-01

The article refers to methane presented in hard coal seams, which may pose a serious risk to workers, as evidenced by examples of incidents, and may also be a high energy source. That second issue concerns the possibility of obtaining methane from liquidated coal mines. There is discussed the current methodology for determination of methane resources from hard coal deposits. Methods of assessing methane emissions from hard coal deposits are given, including the degree of rock mass fracture, which is affected and not affected by mining. Additional criteria for methane recovery from the methane deposit are discussed by one example (of many types) of methane power generation equipment in the context of the estimation of potential viable resources. Finally, the concept of “methane resource exploitation from coal mine” refers to the potential for exploitation of the resource and the acquisition of methane for business purposes.

Improving extraction technology of level seams. Sovershenstvovanie tekhnologii razrabotki pologikh plastov

Energy Technology Data Exchange (ETDEWEB)

Shetser, M G; Spitsyn, Yu G

1985-01-01

This report deals with conditions and prospects for intensifying extraction of level and inclined seams and improving extraction technology. Reviews mechanization of excavation of stables with automatic cutter-loaders (KA80 in conjunction with KD80); coal extraction using two cutter-loaders in seams 0.9 - 1.9 m thick and up to 20 degrees inclination (pillar mining); reciprocating method of coal cutting; one-sided method of coal extraction (KMK97 cutter loaders). Discusses strengthening of junctions of faces with gate roads (KSU and KSU3M props); improved types of props (hydraulic props SUG-30, SUG-V and GVD); roof control methods (induced caving, advance torpedoing or using KM87UMP and KMT power supports). Deals in detail with introduction of new extraction technology and strengthening of unstable rock by injecting polyurethene compounds, extraction of seams with wide-web cutter-loaders (Kirovets, IK101) and plowing. (3 refs.)

Investigation on characterization of Ereen coal deposit

OpenAIRE

S. Jargalmaa; B. Purevsuren; Ya. Davaajav; B. Avid; B. Bat-Ulzii; B. Ochirhuyag

2016-01-01

The Ereen coal deposit is located 360 km west from Ulaanbaatar and 95 km from Bulgan town. The coal reserve of this deposit is approximately 345.2 million tons. The Ereen coal is used directly for the Erdenet power plant for producing of electricity and heat. The utilization of this coal for gas and liquid product using gasification and pyrolysis is now being considered. The proximate and ultimate analysis show that the Ereen coal is low rank D mark hard coal, which corresponds to subbitumino...

Seismic modelling of coal bed methane strata, Willow Creek, Alberta

Energy Technology Data Exchange (ETDEWEB)

Richardson, S.E.; Mayer, R.; Lawton, D.C.; Langenberg, W. [Consortium for Research in Elastic Wave Exploration Seismology, Calgary, AB (Canada)

2001-07-01

The purpose is to determine the feasibility of applying high- resolution reflection seismic surveying to coalbed methane (CBM) exploration and development. Numerical reflection seismic methods are examined for measuring the mapping continuity and coherence of coal zones. Numerical modelling of a coal zone in Upper Cretaceous sediments near Willow Creek, Alberta indicates that seismic data that is predominantly of 100 Hz is required to map the coal zone and lateral facies variations within the deposit. For resolution of individual coal seams, a central frequency >150 Hz would be needed. 26 refs., 17 figs., 3 tabs.

Process for opening up carboniferous seams for underground gasification by drilling production holes downwards

Energy Technology Data Exchange (ETDEWEB)

Lokschin, J L; Volk, A F; Starinskii, A A

1977-12-01

This process will reduce drilling costs and times by 20 to 25% and will improve gasification under the influence of a thin liquid medium connecting adjacent holes. After determining the approximate depth and thickness of the seam to be opened up, e.g. by geological means, production holes of 100 to 400 mm (diameter) are made down to a depth of 400 m or more, by well-known boring bars and chisels. After passing the top of the seam (the roof of the seam), which can be recognised by discoloration of the drilling liquid, one goes 1/2 to 1 metre deeper and one determines the depth of the roof the seam exactly by the reduced natural radioactivity at the boundary layer, by introducing a gamma sensor on to the boring bar. The production holes are taken down in a second borehold to a free space 0.6 to 2 metres above the floor of the seam (bottom of the seam), according to the thickness of the seam. After replacing the boring bar by a feedpipe one continues to drill using a boring bar of smaller cutting diameter inside this tube. This hole reaches from the foot of the pipe of the feedpipe to the floor of the seam. It is preferably flushed with gas but may be flushed with liquid. A thin liquid introduced into this hole penetrates the surrounding mass of the seam horizontally (unhindered by any armouring) and represents the required connection to neighbouring bores for gasification. The process is suitable for mining coal, combustible shale oil, bituminous rock, heavy natural oil where this process is based on gasification, melting or dissolving of those deposits.

Engineering research on coal and gas outburst control for outburst coal seam floor roadway in deep mine%深井突出煤层底板巷防治煤与瓦斯突出工程研究

Institute of Scientific and Technical Information of China (English)

吕有厂; 王玉杰

2017-01-01

文章针对平煤股份首山一矿突出煤层结构复杂、渗透性低,致使预抽煤层瓦斯效果差、效率低的问题,以平煤股份首山一矿突出煤层底板岩巷瓦斯治理工程典型应用模式为研究对象,现场观测分析上覆突出煤层采掘过程中低板岩巷围岩应力变化规律,观测分析卸压瓦斯抽采效果,优化煤岩巷层位关系、为深部突出煤层巷道支护和抽采瓦斯提供指导,对提高深井突出煤层瓦斯治理效果具有重要的借鉴意义.%Aiming at the complex structure and low permeability of outburst coal seam in Shouyishan Coal Mine,resulting in poor effect in the gas pre-drainage,based on the typical application mode of gas control engineering in floor rock roadway of the outburst coal seam,surrounding rock stress variation law of floor rock roadway was observed and analyzed in the field during mining and tunneling in the overlying outburst coal seam.The pressure-relieving gas drainage effect was analyzed,and the position arrangement of coal and rock roadway was optimized.

A Novel Acoustic Liquid Level Determination Method for Coal Seam Gas Wells Based on Autocorrelation Analysis

Directory of Open Access Journals (Sweden)

Ximing Zhang

2017-11-01

Full Text Available In coal seam gas (CSG wells, water is periodically removed from the wellbore in order to keep the bottom-hole flowing pressure at low levels, facilitating the desorption of methane gas from the coal bed. In order to calculate gas flow rate and further optimize well performance, it is necessary to accurately monitor the liquid level in real-time. This paper presents a novel method based on autocorrelation function (ACF analysis for determining the liquid level in CSG wells under intense noise conditions. The method involves the calculation of the acoustic travel time in the annulus and processing the autocorrelation signal in order to extract the weak echo under high background noise. In contrast to previous works, the non-linear dependence of the acoustic velocity on temperature and pressure is taken into account. To locate the liquid level of a coal seam gas well the travel time is computed iteratively with the non-linear velocity model. Afterwards, the proposed method is validated using experimental laboratory investigations that have been developed for liquid level detection under two scenarios, representing the combination of low pressure, weak signal, and intense noise generated by gas flowing and leakage. By adopting an evaluation indicator called Crest Factor, the results have shown the superiority of the ACF-based method compared to Fourier filtering (FFT. In the two scenarios, the maximal measurement error from the proposed method was 0.34% and 0.50%, respectively. The latent periodic characteristic of the reflected signal can be extracted by the ACF-based method even when the noise is larger than 1.42 Pa, which is impossible for FFT-based de-noising. A case study focused on a specific CSG well is presented to illustrate the feasibility of the proposed approach, and also to demonstrate that signal processing with autocorrelation analysis can improve the sensitivity of the detection system.

Pillar size optimization design of isolated island panel gob-side entry driving in deep inclined coal seam—case study of Pingmei No. 6 coal seam

Science.gov (United States)

Zhang, Shuai; Wang, Xufeng; Fan, Gangwei; Zhang, Dongsheng; Jianbin, Cui

2018-06-01

There is a perception that deep roadways are difficult to maintain. To reverse this and to improve the recovery rate of coal resources, gob-side entry driving is widely used in coal mines, especially deep-mining coal mines, in China. Determination of the reasonable pillar size through in situ observation and experimentation plays a vital role for roadway maintenance. Based on the geological conditions of Pingmei No.6 coal seam, a theoretical analysis, numerical simulation, and industrial experiments are carried out to calculate the reasonable width of chain pillars, analyze the lateral support stress distribution law near the gob side, investigate the relationship between the coal pillar stress distribution, roadway surrounding rock stress distribution, roadway surrounding rock deformation and the coal pillar width. The results indicate that 5 m wide coal pillars can ensure that the chain pillars are at a lower stress level and the deformation of roadway surrounding rock is in a more reasonable range. Industrial experiments show that when the chain pillar width is 5 m, the deformation of roadway surrounding rock can meet the requirements of working face safe production. The numerical results agreed well with field measurement and observations, and the industrial experiments results further validated the results of the numerical simulation.

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.

Fossil fuel energy resources of Ethiopia: Coal deposits

Energy Technology Data Exchange (ETDEWEB)

Wolela, Ahmed [Department of Petroleum Operations, Ministry of Mines and Energy, Kotebe Branch Office, P. O. Box-486, Addis Ababa (Ethiopia)

2007-11-22

The gravity of Ethiopian energy problem has initiated studies to explore various energy resources in Ethiopia, one among this is the exploration for coal resources. Studies confirmed the presence of coal deposits in the country. The coal-bearing sediments are distributed in the Inter-Trappean and Pre-Trap volcanic geological settings, and deposited in fluvio-lacustrine and paludal environments in grabens and half-grabens formed by a NNE-SSW and NNW-SSE fault systems. Most significant coal deposits are found in the Inter-Trappean geological setting. The coal and coal-bearing sediments reach a maximum thickness of 4 m and 300 m, respectively. The best coal deposits were hosted in sandstone-coal-shale and mudstone-coal-shale facies. The coal formations of Ethiopia are quite unique in that they are neither comparable to the coal measures of the Permo-Carboniferous Karroo Formation nor to the Late Devonian-Carboniferous of North America or Northwestern Europe. Proximate analysis and calorific value data indicated that the Ethiopian coals fall under lignite to high volatile bituminous coal, and genetically are classified under humic, sapropelic and mixed coal. Vitrinite reflectance studies confirmed 0.3-0.64% Ro values for the studied coals. Palynology studies confirmed that the Ethiopian coal-bearing sediments range in age from Eocene to Miocene. A total of about 297 Mt of coal reserve registered in the country. The coal reserve of the country can be considered as an important alternative source of energy. (author)

Concentration of gallium in the Permo-Carboniferous coals of China

Energy Technology Data Exchange (ETDEWEB)

Zhao, Cunliang; Qin, Shenjun; Yang, Yinchao; Li, Yanheng; Lin, Mingyue [Hebei University of Engineering, Handan (China)

2009-10-15

Gallium is widely used in electronic industry and its current price is about 500 US dollars per kilogram. It has been found that its contents are very high in Permo-Carboniferous coal of China. In order to look for valuable associated gallium deposits in coal, gallium contents of 177 coal samples were determined by using inductively coupled plasma-mass spectrometry (ICP-MS) and the data of 873 coal samples from Chinese Permo-Carboniferous coalfields were collected. The results show that the average gallium concentration of Chinese Permo-Carboniferous coals is 15.49{mu}g{center_dot}g{sup -1}. There are two concentration types of gallium in Chinese Permo-Carboniferous coals: one type is that gallium has enriched to an ore deposit, and another type is that gallium is locally enriched in coal seams, but has not formed a valuable associated gallium ore deposit. The gallium concentration in Chinese Permo-Carboniferous coal may have several different sources: concentration in sedimentation stage, magmatic hydrothermal inputs and low-temperature hydrothermal fluids.

Liquefaction of Warukin Formation Coal, Barito Basin, South Kalimantan on Low Pressure and Low Temperature

Directory of Open Access Journals (Sweden)

Edy Nursanto

2013-06-01

Full Text Available Research focusing on the quality of coal in Warukin Formation has been conducted in coal outcrops located on Tabalong area, particularly in 3 coal seams, namely Wara 120 which consists of low rank coal (lignite. Meanwhile, coals in seam Tutupan 210 and Paringin 712 are medium rank coal (sub-bituminous. Coal liquefaction is conducted in an autoclave on low pressure and temperature. Pressure during the process is 14 psi and temperature is 120oC. Catalyst used are alumina, hydrogen donor NaOH and water solvent. Liquefaction is conducted in three times variables of 30 minutes, 60 minutes and 90 minutes. This process shows following yield : Wara seam 120: 25.37% - 51.27%; Tutupan seam 210: 3.02%-15.45% and seam Paringin 712:1.99%-11.95%. The average result of yield shows that coals in seam Wara has higher yield conversion than coals in seam Tutupan and Paringin.

Lithostratigraphy, depositional environments and sedimentology of the Permian Vryheid Formation (Karoo Supergroup), Arnot North, Witbank Coalfield, South Africa

OpenAIRE

2009-01-01

M.Sc. This work documents the lithostratigraphy and interpreted depositional environments of the Permian Vryheid Formation in the most northern proximal setting yet studied in the Witbank Coalfield. Data from 924 boreholes from two mining companies (Anglo Operations Ltd. and Xstrata Coal Ltd.) drilled over 50 years, covering an area of 910km2 revealed a 35m sequence of terrigenous clastic sedimentary rocks containing two coal seams. These seams are numbered No. 1 at the base and No. 2 at t...

Organic petrology, mineralogy and depositional environment of the Kipra lignite seam, Maritza-West basin, Bulgaria

Energy Technology Data Exchange (ETDEWEB)

Kostova, Irena [Department of Geology and Palaeontology, Sofia University ' ' St. Kliment Ohridski' ' , 1000, Sofia (Bulgaria); Zdravkov, Alexander [Department of Economic Geology, University of Mining and Geology ' ' St. Ivan Rilski' ' , 1700, Sofia (Bulgaria)

2007-08-01

The aim of the present study is to provide additional information about the properties and depositional environment of the Kipra lignite seam, which was deposited during the regressive stage of development of the Maritza-West basin. Petrographical and mineralogical data, along with ash yields and sulphur contents of 24 samples from a seam profile, have been used to study the vertical variation of the depositional settings during peat accumulation and subsequent coalification. The Kipra lignite is characterized by high ash yields and sulphur contents. It formed in a rheotrophic, low-lying mire with alkaline pH value. Vegetation with low preservation potential dominated within the palaeomire. During peat formation, frequent changes of the water level controlled the depositional environment. During the deposition of units 1 and 2, high water energy caused the transportation of high amounts of inorganic material into the mire, resulting in the formation of weakly gelified mineral-rich lignite. The organic matter from units 3 and 4 is characterized by enhanced gelification, which probably reflects the decreasing energy of the system. Good positive correlation between sulphur contents and the GI values was established in units 4, indicating that the gelification of the tissues was probably mainly controlled by the bacterial activity. In contrast, the gelification of the samples from unit 3 of the Kipra seam was probably governed by the redox conditions. The organic matter deposited under relatively wet conditions, in which the thermal and oxidative destruction of the tissues, was limited. A variety of major, minor and accessory minerals are present in Maritza-West lignite. The mineral composition is dominated mainly by pyrite, gypsum and calcite, and to a lesser extent limonite, quartz, kaolinite, montmorillonite, illite, chlorite and plagioclase. Jarosite, hematite, halloysite, mica, K-feldspar, aragonite, siderite, and dolomite were also determined in very low

Oxidation and carbonisation of coals: a case study of coal fire affected coals from the Wuda coalfield, Inner Mongolia, China

Science.gov (United States)

Kus, Jolanta; Meyer, Uwe; Ma, Jianwei; Chen-Brauchler, Dai

2010-05-01

At the coalfield of Wuda (Inner Mongolia, PR China) extensive underground coal fires cause widespread thermal and oxidative effects in coal seams. Within phase B of the Coal Fire Research Project of the Sino-German Initiative, methods for innovative fire-extinguishing technologies were investigated in multifaceted research approaches. Extensive investigations of oxidative and thermally affected coal seams in coal fire zone 18 were conducted in 2008 prior to application of new fire-extinguishing methods. We present results from the outcrop of coal seam No. 4 in the fire zone 18. The coal of seam No. 4 is of Early Permian age and belongs stratigraphically to the Shanxi Formation. The unaffected coal displays a high volatile bituminous A rank with a background value of random vitrinite reflectance ranging from 0.90 to 0.96 % Rr. Coal channel samples were coallected at actively extracted coal faces along multiple profiles with surface temperatures ranging from about 50° to 600°C. Microscopic examinations revealed a variety of products of coal exposure to the fire. Within coal samples, a marked rise in vitrinite reflectance from background values to 5.55% Rr (6.00 % Rmax) is encountered. In addition, a number of coal samples showed suppressed vitrinite reflectances ranging between 0.82 to 0.88% Rr. Further, seemingly heat unaffected coal samples display intensive development of oxidations rims at coal grain edges and cracks as well as shrinkage cracks and formation of iron oxides/hydroxides. Instead, thermally affected coal samples with higher coalification grade are further characterised by development of macropores (devolatilisation pores) in vitrinitic streaks, transformation of liptinite to meta-liptinite and micrinite as well as by natural coke particles of mostly porous nature and fine to coarse grained anisotropic mosaic. Coal petrographic investigations confirmed a hypothesis that both, oxidations as well as low temperature carbonisation govern the thermal

Sequence stratigraphic analysis and the origins of Tertiary brown coal lithotypes, Latrobe Valley, Gippsland Basin, Australia

Energy Technology Data Exchange (ETDEWEB)

Holdgate, G R; Kershaw, A P; Sluiter, I R.K. [Monash University, Clayton, Vic. (Australia). Dept. of Earth Sciences

1995-11-01

Sequence analysis methods have been applied to the onshore Gippsland Basin and to the Latrobe Valley Group coal measures. In the east of the Latrobe Valley evidence for marine transgressions into the coal measures are recorded in most of the interseam sediment splits by the presence of contained foraminifer and dinoflagellates. To the west these splits pinch out into continuous coal. However, they can be followed westwards as enhanced organic sulphur levels along sharply defined boundaries between light coal lithotypes below and dark coal lithotypes above. The dark lithotype immediately overlying each of these boundaries contains the highest sulphur value and warmer climate pollen assemblages. Colorimeter and lithotype logging supports an upwards lightening cyclicity to coal colour at 12-20 m intervals through the approx. 100 m thick seams, with cycle boundaries defined at sharp planar to undulating surfaces. The lightening upward lithotype cycles together with their unique boundary conditions are interpreted as parasequences and parasequence boundaries respectively. Each major coal seam can comprise up to five parasequences and is interpreted to represent deposition during an outbuilding high stand systems tract at one of several maximum periods of Tertiary coastal onlap. Stratigraphic correlation of the sequence boundaries identified in the coal measures to the internationally dated marine Seaspray Group, provides a basis for chronostratigraphic correlation of the coal successions to the coastal onlap charts of Haq et al (1989). It appears that each major seam is confined to high standards of third order eustatic cycles. It follows that the lithotype cycles that comprise each seam are related to fourth order eustatic cycles. 49 refs., 11 figs., 1 tab.

Geochemistry of environmentally sensitive trace elements in Permian coals from the Huainan coalfield, Anhui, China

Science.gov (United States)

Chen, J.; Liu, Gaisheng; Jiang, M.; Chou, C.-L.; Li, H.; Wu, B.; Zheng, Lingyun; Jiang, D.

2011-01-01

To study the geochemical characteristics of 11 environmentally sensitive trace elements in the coals of the Permian Period from the Huainan coalfield, Anhui province, China, borehole samples of 336 coals, two partings, and four roof and floor mudstones were collected from mineable coal seams. Major elements and selected trace elements were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and hydride generation atomic absorption spectrometry (HAAS). The depositional environment, abundances, distribution, and modes of occurrence of trace elements were investigated. Results show that clay and carbonate minerals are the principal inorganic constituents in the coals. A lower deltaic plain, where fluvial channel systems developed successively, was the likely depositional environment of the Permian coals in the Huainan coalfield. All major elements have wider variation ranges than those of Chinese coals except for Mg and Fe. The contents of Cr, Co, Ni, and Se are higher than their averages for Chinese coals and world coals. Vertical variations of trace elements in different formations are not significant except for B and Ba. Certain roof and partings are distinctly higher in trace elements than underlying coal bench samples. The modes of occurrence of trace elements vary in different coal seams as a result of different coal-forming environments. Vanadium, Cr, and Th are associated with aluminosilicate minerals, Ba with carbonate minerals, and Cu, Zn, As, Se, and Pb mainly with sulfide minerals. ?? 2011 Elsevier B.V.

Influence of lithological characters of coal bearing formation on stability of roof of coal seams

Energy Technology Data Exchange (ETDEWEB)

Meng Zhao-ping; Peng Su-ping; Li Guo-qing; Huang Wei; Lu Jun; Lei Zhi-yong [CUMT, Beijing (China). School of Resources and Safety Engineering

2003-07-01

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.

Detection of Coal Fires: A Case Study Conducted on Indian Coal Seams Using Neural Network and Particle Swarm Optimization

Science.gov (United States)

Singh, B. B.

2016-12-01

India produces majority of its electricity from coal but a huge quantity of coal burns every day due to coal fires and also poses a threat to the environment as severe pollutants. In the present study we had demonstrated the usage of Neural Network based approach with an integrated Particle Swarm Optimization (PSO) inversion technique. The Self Potential (SP) data set is used for the early detection of coal fires. The study was conducted over the East Basuria colliery, Jharia Coal Field, Jharkhand, India. The causative source was modelled as an inclined sheet like anomaly and the synthetic data was generated. Neural Network scheme consists of an input layer, hidden layers and an output layer. The input layer corresponds to the SP data and the output layer is the estimated depth of the coal fire. A synthetic dataset was modelled with some of the known parameters such as depth, conductivity, inclination angle, half width etc. associated with causative body and gives a very low misfit error of 0.0032%. Therefore, the method was found accurate in predicting the depth of the source body. The technique was applied to the real data set and the model was trained until a very good correlation of determination `R2' value of 0.98 is obtained. The depth of the source body was found to be 12.34m with a misfit error percentage of 0.242%. The inversion results were compared with the lithologs obtained from a nearby well which corresponds to the L3 coal seam. The depth of the coal fire had exactly matched with the half width of the anomaly which suggests that the fire is widely spread. The inclination angle of the anomaly was 135.510 which resembles the development of the geometrically complex fracture planes. These fractures may be developed due to anisotropic weakness of the ground which acts as passage for the air. As a result coal fires spreads along these fracture planes. The results obtained from the Neural Network was compared with PSO inversion results and were found in

Solid Coal Stability with Regards to Seam Thickness or Bench mined

Directory of Open Access Journals (Sweden)

Bukovanský Stanislav

1998-03-01

Full Text Available In the paper the problem of working unit stability, showing a limit state of a rock tension with the Mohr envelope known from a theory of failure, is described. It is obvious that a load of building units in mountain massives can be expressed easily either by simple or multiaxial compressions, and then, on the basis of individual states characteristics, individual conditions of stability can be observed. So we may understand that such building units can be broken even in case of a certain discharge, i.e. lowering of one of main tensions of both of them as well. Combined methods of discharge and surchage can be used too. Another reactive power of an enormous value is caused by pre-fault then. In the OKR district it means even 10% of the seam thickness with common conditions (e.g. saddle seams. An area of a contact between a seam, original rocks and seam thickness should be taken into consideration as serious conditions of rock bumps origin. If this contact area is wavy of the seam thickness is small (possibly both conditions are valid, there will be no risk of any rock bump.

The Mine Working's Roof Stress-strain State Research in the Perspective of Development of New Coal Deposits of Kuzbass

Science.gov (United States)

Kostyuk, Svetlana; Bedarev, Nikolay; Lyubimov, Oleg; Shaikhislamov, Arthur

2017-11-01

The present now normative and information base is regulating of the Kuzbass coal seams treatment but is not considering of the mining-geological and mining-engineering conditions for new coal deposits. The analysis of works for the research of the rock pressure manifestation shows that in many cases numerous results require of the practical confirmation in mine conditions directly, and also confirmation by the physical models. This work reflects one of the stages of research on changing the stress-strain state of the massif with the formation of unloading zones, increased rock pressure, and recovery. As an example, the results of the information analysis obtained by means of contour and depth benchmarks on the ventilation drift in the course of the 34 seam treatment at the "Tagaryshskaya" mine are presented. The differences of the analyzed results from the results obtained in the conditions of other mines are established. The values of the drift's roof stratification on the contour and at the distance from the contour of 1.0 to 4.0 m are given. The revealed maximums of the rock pressure and pressure changes in the hydraulic supports of the complex used for movement are presented. Recommendations on the choice of the anchor's length taking into account the roof stratification size are given. The further research stages on models from equivalent materials at various geometric scales are proposed.

Mechanization of operations in underground workings in coal mines and research project trends. [Poland

Energy Technology Data Exchange (ETDEWEB)

Reich, K; Skoczynski, W; Sikora, W

1985-01-01

Structure of black coal reserves of Poland, imported and Polish made equipment for underground mining, prospects for mechanization of selected operations in underground mines and research programs of the KOMAG Center for Mechanization of Mining are evaluated. Prospects for longwall mining with caving or stowing in thick coal seams (slice mining), thin (0.8 to 1.2 m), level or inclined coal seams and steep seams are analyzed. The following equipment for mechanization of underground mining is evaluated: integrated face systems, shearer loaders, chain conveyors, belt conveyors, coal plows, equipment for mine drivage, hoists, drive systems for mining equipment. The following research programs of the KOMAG Center are reviewed: modernization of face systems for coal seams with uncomplicated mining conditions, development of equipment for thin seam mining, development of types of mining equipment for coal seams from 1.5 to 3.0 m thick with dip angles to 25 degrees, modernization of equipment for thick seam mining, increasing efficiency of mine drivage (new types of heading machines, materials handling equipment for mine drivage), mechanization of auxiliary operations in underground coal mines, improving quality of mining equipment, development of equipment for coal preparation, increasing occupational safety in underground mining.

Investigation on characterization of Ereen coal deposit

Directory of Open Access Journals (Sweden)

S. Jargalmaa

2016-03-01

Full Text Available The Ereen coal deposit is located 360 km west from Ulaanbaatar and 95 km from Bulgan town. The coal reserve of this deposit is approximately 345.2 million tons. The Ereen coal is used directly for the Erdenet power plant for producing of electricity and heat. The utilization of this coal for gas and liquid product using gasification and pyrolysis is now being considered. The proximate and ultimate analysis show that the Ereen coal is low rank D mark hard coal, which corresponds to subbituminous coal. The SEM images of initial coal sample have compact solid pieces. The SEM image of carbonized and activated carbon samples are hard material with high developed macro porosity structure. The SEM images of hard residue after thermal dissolution in autoclave characterizes hard pieces with micro porous structure in comparison with activated carbon sample. The results of the thermal dissolution of Ereen coal in tetralin with constant weight ratio between coal and tetralin (1:1.8 at the 450ºC show that 38% of liquid product can be obtained by thermal decomposition of the COM (coal organic matter.Mongolian Journal of Chemistry 16 (42, 2015, 18-21

Electrical and gamma-ray logging in Gondwana and Tertiary coal fields of India

International Nuclear Information System (INIS)

Kayal, J.R.

1979-01-01

Electrical and gamma-ray logging have been very useful for identification and accurate determination of depth and thickness of coal seams in Gondwana and Tertiary coal fields of India. The characteristic resistance/resistivity peaks of coal seams in a particular area have been correlated, thus providing a picture of the subsurface structure. Physico-chemical properties of layers or sections of coal seams are responsive to electrical logs. Gamma-ray logs are found to be very useful for correlation and have sometimes been the only logs used in cased and dry boreholes for detection of coal seams. Under favourable conditions a single-point resistance log reveals a detailed picture of the formations and picks up thin coal seams as well as thin shale bands within the coal seam. But in some cases it fails to differentiate between coal and sandstone beds in spite of high contrast in true resistivities. Multi-electrode long-normal and lateral logs are found to be more useful in differentiating such formations because of higher penetration in this system. Long-normal and lateral curves can also be used to determine true resisvity of the formation. But long normal logs cannot pick up thin coal bands and/or thin shale partings within the coal seam because of the 'adjacent bed effect'. Gamma-ray logging can be done in both cased and uncased bore-holes or even in a dry borehole but its resolution for shaly coal or thin coal is not sufficient. Combined study has been found to yield the best results. (Auth.)

Numerical simulation of head top coal's stability control of fully mechanized longwall mining with sublevel caving face in large dip seam

Energy Technology Data Exchange (ETDEWEB)

Li, W.; Wan, Z.; Jiang, F.; Jia, P. [Beijing Science and Technology University, Beijing (China)

2008-07-01

Stability control of the head face's top-coal is one of the key techniques of realising high production and high efficiency in coal mining in fully mechanized top-coal caving face. The characteristics of the stress in the overlying strata of the fully mechanized top-coal caving face and the top coal were analysed using FLAC{sup 3D}. The results show that the tip-to-face top-coal generates a large deformation while it is in the stress-relaxed area. The top-coal in the front of the wall appears to be the failure area for the effect of the abutment pressure that spreads over the coal seam. The surrounding rock of the upper face end is the key part strengthened the control of the rib spalling. The first and frequent appearing phenomenon of losing stability of the powered supports is that the back base of the hydraulic power supports in the top of the face slips. Increasing the quality of support and so on can maintain the stability of surrounding rock. 4 refs., 7 figs., 1 tab.

Dating of authigenic clays related to igneous intrusions in Hunter Valley Coals

International Nuclear Information System (INIS)

Zwingmann, H.

2000-01-01

The Sydney Basin is composed mainly of Permian and Triassic marine and non-marine clastic sedimentary strata together with economically significant coal deposits and volumetrically minor igneous rocks. Many of these igneous rocks are also economically significant not only for their use in the construction industry but also for their deleterious effects on coal mining, particularly in underground mines utilising longwall extraction systems. Igneous activity in the Sydney Basin ranges from Early Permian to Tertiary in age and although episodic in nature, activity was unlikely to have ceased for periods of more than approximately 10 million years (Carr and Facer 1980; Embleton et al. 1982). Dating of the time of emplacement of igneous rocks using the K-Ar isotopic system is a relatively straightforward procedure if suitable analytical facilities and samples of appropriate, fresh, primary minerals are available. In the case of intrusions in coal seams, however, the occurrence of fresh, primary minerals is very rare due to widespread alteration produced by interaction between the igneous rock and fluids in the coal seam. This interaction produces a variety of secondary minerals with most primary minerals and glass being altered to clays (mainly kaolinite) and carbonates. Consequently, relatively few isotopic dates for intrusions into coal seams have been determined. A detailed study of several hundred samples of igneous rocks from the Sydney Basin found only six samples of intrusions into coal seams that were suitable for conventional K-Ar dating (Carr and Facer 1980). Techniques for K-Ar dating of authigenic illite, developed in response to the need by the petroleum industry to understand the timing of diagenesis in petroleum source-rocks and reservoirs, are now well established (Clauer and Chaudhuri 1995). As part of a larger project on the impact of igneous intrusions on coal mining and the alienation of coal reserves, a preliminary investigation of the timing of

Characterization of coals from the Ravenscrag Formation, southern Saskatchewan, Canada

Energy Technology Data Exchange (ETDEWEB)

McDougall, W.J. (University of Regina, Regina, SK (Canada). Faculty of Science)

1989-10-30

Samples of economically important lignite reserves in the Ravenscrag Formation (Paleocene) of southern Saskatchewan are characterized by lithotype, maceral, microlithotype, and chemical analysis. The samples are from two cores and five reverse circulation drill boreholes from the Hart seam, Willow Bunch coalfield. Samples from four reverse circulation boreholes from the Souris seam, Estevan coalfield are characterized by maceral and chemical analysis. Coals from the Hart and Souris seams differ in rank, because of different thermal histories. A microlithotype classification developed for low rank coals is presented for Hart seam coals. 74 refs., 35 figs., 12 tabs.

Fiscal 1999 research cooperation project report. Research cooperation on coal liquefaction technology; 1999 nendo sekitan ekika gijutsu ni kansuru kenkyu kyoryoku jigyo

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

This report summarizes the fiscal 1999 research cooperation project result on coal liquefaction technology. Cooperative FS was made on coal liquefaction technology of Indonesian coal as petroleum substituting energy. To obtain the basic data necessary for the FS, study was made on the applicability of Indonesian natural minerals as catalytic materials. Promising low-cost abundant Soroako Limonite ore showed a high catalytic activity for liquefaction reaction of Banko coal, and an excellent grindability. Improved BCL process including hydrogenation process was promising for production of high-quality coal liquid superior in storage stability with less nitrogen and sulfur contents. Survey was made on the general conditions of Tanjung Enim area including South Banko coal field concerned, and the geological features and coal seam of South Banko coal field which is composed of 3 seams including coal deposits of 6.35 hundred million tons. To study the marketability of coal liquid, survey was made on the current situation of oil, oil product standards, and blendability of coal liquid. Hydrogen for the liquefaction process can be obtained by coal gasification. (NEDO)

A brief introduction to the Tavan Tolgoi coking coal deposit

Energy Technology Data Exchange (ETDEWEB)

1992-01-01

The Tavan Tolgoi coal field is located near the settlement Tsogttsetsii in the South Gobi province, 540 km south of Ulaanbaatar and 96 km east of Dalan Zadgad. The nearest railway stations are Choir, Khar-Airag and Sainshand and are located a distance of about 390 to 450 km, to the northeast of the coal field. An unimproved road connects the property with the railway stations at this time. The Tavan Tolgoi coal field covers 220 square km of land. The coal bearing strata contains 16 coal seams from 3 to 30 m thick with a total average thickness of 165 m. As per the geological survey, the proven and probable reserves of the Tavan Tolgoi coal field are estimated at 5 billion tonnes. Of the 5 billion tonnes, 77.5% or 3.9 billion tonnes are expected to be washed and will produce 2.16 billion tonnes (55% wash recovery) of clean coking coal. 1.41 billion tonnes or 36% of the washed coal will be middlings and available for steam coal, and 9% or 0.33 billion tonnes will be washed or gob. The remaining 1.2 billion tonnes can be mined and sold raw as steam coal. Water, electricity supplies and transportation will have to be developed. Research on this has been done. Markets are envisaged to be within Mongolia, and in the Asia Pacific region. Foreign investment will be needed. 5 figs., 6 tabs.

Underground Coal Thermal Treatment

Energy Technology Data Exchange (ETDEWEB)

Smith, P. [Univ. of Utah, Salt Lake City, UT (United States); Deo, M. [Univ. of Utah, Salt Lake City, UT (United States); Eddings, E. [Univ. of Utah, Salt Lake City, UT (United States); Sarofim, A. [Univ. of Utah, Salt Lake City, UT (United States); Gueishen, K. [Univ. of Utah, Salt Lake City, UT (United States); Hradisky, M. [Univ. of Utah, Salt Lake City, UT (United States); Kelly, K. [Univ. of Utah, Salt Lake City, UT (United States); Mandalaparty, P. [Univ. of Utah, Salt Lake City, UT (United States); Zhang, H. [Univ. of Utah, Salt Lake City, UT (United States)

2012-01-11

The long-term objective of this work is to develop a transformational energy production technology by insitu thermal treatment of a coal seam for the production of substitute natural gas (SNG) while leaving much of the coal's carbon in the ground. This process converts coal to a high-efficiency, low-GHG emitting gas fuel. It holds the potential of providing environmentally acceptable access to previously unusable coal resources. This topical report discusses the development of experimental capabilities, the collection of available data, and the development of simulation tools to obtain process thermo-chemical and geo-thermal parameters in preparation for the eventual demonstration in a coal seam. It also includes experimental and modeling studies of CO₂ sequestration.

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.

Depositional sequence stratigraphy and architecture of the cretaceous ferron sandstone: Implications for coal and coalbed methane resources - A field excursion

Science.gov (United States)

Garrison, J.R.; Van Den, Bergh; Barker, C.E.; Tabet, D.E.

1997-01-01

This Field Excursion will visit outcrops of the fluvial-deltaic Upper Cretaceous (Turonian) Ferron Sandstone Member of the Mancos Shale, known as the Last Chance delta or Upper Ferron Sandstone. This field guide and the field stops will outline the architecture and depositional sequence stratigraphy of the Upper Ferron Sandstone clastic wedge and explore the stratigraphic positions and compositions of major coal zones. The implications of the architecture and stratigraphy of the Ferron fluvial-deltaic complex for coal and coalbed methane resources will be discussed. Early works suggested that the southwesterly derived deltaic deposits of the the upper Ferron Sandstone clastic wedge were a Type-2 third-order depositional sequence, informally called the Ferron Sequence. These works suggested that the Ferron Sequence is separated by a type-2 sequence boundary from the underlying 3rd-order Hyatti Sequence, which has its sediment source from the northwest. Within the 3rd-order depositional sequence, the deltaic events of the Ferron clastic wedge, recognized as parasequence sets, appear to be stacked into progradational, aggradational, and retrogradational patterns reflecting a generally decreasing sediment supply during an overall slow sea-level rise. The architecture of both near-marine facies and non-marine fluvial facies exhibit well defined trends in response to this decrease in available sediment. Recent studies have concluded that, unless coincident with a depositional sequence boundary, regionally extensive coal zones occur at the tops of the parasequence sets within the Ferron clastic wedge. These coal zones consist of coal seams and their laterally equivalent fissile carbonaceous shales, mudstones, and siltstones, paleosols, and flood plain mudstones. Although the compositions of coal zones vary along depositional dip, the presence of these laterally extensive stratigraphic horizons, above parasequence sets, provides a means of correlating and defining the tops

Causes of coal degradation at working faces

Energy Technology Data Exchange (ETDEWEB)

Sikora, W

1985-01-01

Coal comminution by shearer loaders at working faces and factors influencing it are analyzed. Three groups of factors are evaluated: coal mechanical properties, design and specifications of shearer loaders and mining schemes. On the basis of analyses, recommendations for increasing proportion of coarse coal and reducing coal comminution in underground coal mines in Poland are made. Increasing output of coarse coal in coal seams with a high proportion of dull coal is most economic. Increasing power of drive systems for shearer loaders to 500 kW or more decisively influences grain size distribution of coal and increases proportion of coarse coal, especially in seams of dull coal. Gradually increasing cutting depth of a shearer loader negatively influences haulage speed and coarse coal output. Replacing gradual cutting depth increase by attack at the full cutting depth increases proportion of coarse coal. When medium or thick coal seams are mined a coal bench from 0.3 to 0.5 m thick should be left in the roof or between 2 benches cut by 2 cutting drums. The coal bench left in the face disintegrates under the influence of gravity and the proportion of coarse coal increases. Optimizing yield strength of powered supports at a working face is a further method for improving grain size distribution of coal and increasing proportion of coarse coal. 2 references.

Fiscal 1985 research report. Feasibility study on overseas coal mine development (La Loma coal field, Cesar province, Columbia); 1985 nendo kaigaitan kaihatsu kanosei chosa hokokusho. Columbia Censar shu La Loma tanden

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-01

Tomen Corp. was proposed in April 1985 to join in the additional exploration of La Loma mine lot in 1986 through Greenley Co. in America, one of the members of Siminera- Greenley Association which has promoted the survey and exploration of La Loma coal mine lot (20,000ha), Cesar province, Columbia since 1979. In answer to this proposal, Tomen obtained the fiscal 1985 feasibility study subsidy for foreign coal development, and made surveys on the coal seam, coal property, coal deposit, recoverable deposit and profitability of La Loma coal field including La Loma coal mine lot, and further surveys on infrastructure improvement for the future coal development, the policy of Columbian government and various laws concerned. Based on the above survey results, for assessment of this coal field, Tomen Corp. made field survey on the coal field and infrastructures, document collection and hearing from Columbian and U.S. governments and companies, further collection of other documents concerned and information, and analysis of the survey results. As a result, the assessment of La Loma coal field was completed. (NEDO)

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.

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.

Selected problems of coal mining mechanization in the coal industry of Poland

Energy Technology Data Exchange (ETDEWEB)

Antoniak, J; Sikora, W [Politechnika Slaska, Gliwice (Poland)

1987-01-01

Discusses conditions for underground coal mining in Poland, types of equipment for coal cutting, mine haulage and strata control and development trends of mining technologies. In 1985, black coal output was 191.6 Mt; 85.3% came from longwall faces mined by sets of mining equipment (coal cutters, chain conveyors and powered supports). The average coal output per longwall face was 881 t/d, output per face mined by sets for mining equipment was 1,134 t/d. In 1985, 653 shearer loaders and 77 coal plows were used in Polish coal mines. Number of shearer loaders is increasing. Shearer loaders with chainless haulage system were safest and most economic. The shearer loaders were equipped with the POLTRAK chainless haulage system developed in Poland. Research programs concentrate on development of new mining equipment for thin seam mining, steep seam mining, longwall mining with hydraulic stowing, efficient strata control by powered or shield supports under conditions of increased stresses or rock burst hazards. 4 refs.

Origin of banded structure and coal lithotype cycles in Kargali coal ...

Indian Academy of Sciences (India)

field of Jharkhand, the in situ plant growth is reported (Niyogi 1966; Banerjee 2005). ... organic compounds contribute to coal seam forma- tion (Stach et al. 1982). .... Permian Gondwana coals under fluorescence microscopy;. Gondwana Res.

Data base for the analysis of compositional characteristics of coal seams and macerals. Final report - Part 10. Variability in the inorganic content of United States' coals: a multivariate statistical study

Energy Technology Data Exchange (ETDEWEB)

Glick, D.C.; Davis, A.

1984-07-01

The multivariate statistical techniques of correlation coefficients, factor analysis, and cluster analysis, implemented by computer programs, can be used to process a large data set and produce a summary of relationships between variables and between samples. These techniques were used to find relationships for data on the inorganic constituents of US coals. Three hundred thirty-five whole-seam channel samples from six US coal provinces were analyzed for inorganic variables. After consideration of the attributes of data expressed on ash basis and whole-coal basis, it was decided to perform complete statistical analyses on both data sets. Thirty variables expressed on whole-coal basis and twenty-six variables expressed on ash basis were used. For each inorganic variable, a frequency distribution histogram and a set of summary statistics was produced. These were subdivided to reveal the manner in which concentrations of inorganic constituents vary between coal provinces and between coal regions. Data collected on 124 samples from three stratigraphic groups (Pottsville, Monongahela, Allegheny) in the Appalachian region were studied using analysis of variance to determine degree of variability between stratigraphic levels. Most variables showed differences in mean values between the three groups. 193 references, 71 figures, 54 tables.

Fast and safe gas detection from underground coal fire by drone fly over.

Science.gov (United States)

Dunnington, Lucila; Nakagawa, Masami

2017-10-01

Underground coal fires start naturally or as a result of human activities. Besides burning away the important non-renewable energy resource and causing financial losses, burning coal seams emit carbon dioxide, carbon monoxide, sulfur oxide and methane, and is a leading cause of smog, acid rain, global warming, and air toxins. In the U.S. alone, the combined cost of coal-fire remediation projects that have been completed, budgeted, or projected by the U.S. Department of the Interior's Office of Surface Mining Remediation and Enforcement (OSM), exceeds $1 billion. It is estimated that these fires generate as much as 3% of the world's annual carbon dioxide emissions and consume as much as 5% of its minable coal. Considering the magnitude of environmental impact and economic loss caused by burning underground coal seams, we have developed a new, safe, reliable surface measurement of coal fire gases to assess the nature of underground coal fires. We use a drone mounted with gas sensors. Drone collected gas concentration data provides a safe alternative for evaluating the rank of a burning coal seam. In this study, a new method of determining coal rank by gas ratios is developed. Coal rank is valuable for defining parameters of a coal seam such as burn temperature, burn rate, and volume of burning seam. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coal reserves and resources as well as potentials for underground coal gasification in connection with carbon capture and storage (CCS)

Science.gov (United States)

Ilse, Jürgen

2010-05-01

Coal is the energy source with the largest geological availability worldwide. Of all non-renewable energies coal and lignite accounting for 55 % of the reserves and some 76 % of the resources represent the largest potential. Reserves are those geological quantities of a mineral which can currently be mined under technically and economically viable conditions. Resources are those quantities which are either proven but currently not economically recoverable or quantities which can still be expected or explored on the basis of geological findings. The global availability of energy source does not only depend on geological and economic factors. The technical availability, e.g. mining and preparation capacities, the sufficient availability of land and sea-borne transportation as well as transloading capacities and also a political availability are required likewise. The latter may be disturbed by domestic-policy disputes like strikes or unrest or by foreign-policy disputes like embargos, trade conflicts or even tensions and wars in the producing regions. In the energy-economic discussion the reach of fossil primary energies plays a central role with the most important questions being: when will which energy source be exhausted, which impact will future developments have on the energy price, what does the situation of the other energies look like and which alternatives are there? The reach of coal can only be estimated because of the large deposits on the one hand and the uncertain future coal use and demand on the other. The stronger growth of population and the economic catching-up process in the developing and threshold countries will result in a shift of the production and demand centres in the global economy. However, also in case of further increases the geological potential will be sufficient to reliably cover the global coal demand for the next 100 years. The conventional mining of seams at great depths or of thin seams reaches its technical and economic limits

Geological Factors and Reservoir Properties Affecting the Gas Content of Coal Seams in the Gujiao Area, Northwest Qinshui Basin, China

Directory of Open Access Journals (Sweden)

Zhuo Zou

2018-04-01

Full Text Available Coalbed methane (CBM well drilling and logging data together with geological data were adopted to provide insights into controlling mechanism of gas content in major coal seams and establish gas accumulation models in the Gujiao area, Northwest Qinshui Basin, China. Gas content of targeted coals is various in the Gujiao area with their burial depth ranging from 295 to 859 m. Highly variable gas content of coals should be derived from the differences among tectonism, magmatism, hydrodynamism, and sedimentation. Gas content preserved in the Gujiao area is divided into two parts by the geological structure. Gas tends to accumulate in the groundwater stagnant zone with a total dissolved solids (TDS value of 1300–1700 ppm due to water pressure in the Gujiao area. Reservoir properties including moisture content, minerals, and pore structure also significantly result in gas content variability. Subsequently, the gray correlation statistic method was adopted to determine the most important factors controlling gas content. Coal metamorphism and geological structure had marked control on gas content for the targeted coals. Finally, the favorable CBM exploitation areas were comprehensively evaluated in the Gujiao area. The results showed that the most favorable CBM exploitation areas were in the mid-south part of the Gujiao area (Block I.

Effect of coal stress on grain size of the gotten

Energy Technology Data Exchange (ETDEWEB)

Sikora, W; Tront, A

1988-09-01

Presents investigation results on the effect of seam stress and strain state on winning as measured by the grain size of the gotten. The investigations were carried out at the Institute of Mining Mechanization of the Silesian Politechnical where the relations between parameters of seams and cutters and their effect on coal grain size and energy consumption have been studied for several years. The effect was examined on coal samples taken from 4 mines in the Upper Silesian coal basin using a model of the system: seam - cutter. Cubic samples (400x400x400 mm) were tested on the CMG KOMAG test stand equipped with the POS-1 cutting apparatus. Two types of coal were distinguished: that particularly sensitive to increased pressure on seam and that only negligibly susceptible. Corresponding graphs of coal grain size versus vertical pressure are shown. A function has been developed that characterizes this sensitivity depending on a material parameter that can be determined by workability tests. The relationship between coal strength and grain size yield greater than 10 mm in the gotten depending on dynamic crushability of coal is shown in graphs. 6 refs.

Analysis on the Initial Cracking Parameters of Cross-Measure Hydraulic Fracture in Underground Coal Mines

Directory of Open Access Journals (Sweden)

Yiyu Lu

2015-07-01

Full Text Available Initial cracking pressure and locations are important parameters in conducting cross-measure hydraulic fracturing to enhance coal seam permeability in underground coalmines, which are significantly influenced by in-situ stress and occurrence of coal seam. In this study, stress state around cross-measure fracturing boreholes was analyzed using in-situ stress coordinate transformation, then a mathematical model was developed to evaluate initial cracking parameters of borehole assuming the maximum tensile stress criterion. Subsequently, the influences of in-situ stress and occurrence of coal seams on initial cracking pressure and locations in underground coalmines were analyzed using the proposed model. Finally, the proposed model was verified with field test data. The results suggest that the initial cracking pressure increases with the depth cover and coal seam dip angle. However, it decreases with the increase in azimuth of major principle stress. The results also indicate that the initial cracking locations concentrated in the second and fourth quadrant in polar coordinate, and shifted direction to the strike of coal seam as coal seam dip angle and azimuth of maximum principle stress increase. Field investigation revealed consistent rule with the developed model that the initial cracking pressure increases with the coal seam dip angle. Therefore, the proposed mathematical model provides theoretical insight to analyze the initial cracking parameters during cross-measure hydraulic fracturing for underground coalmines.

Lacustrine basin evolution and coal accumulation of the Middle Jurassic in the Saishiteng coalfield, northern Qaidam Basin, China

Directory of Open Access Journals (Sweden)

Meng Li

2016-07-01

Full Text Available Based on an extensive borehole survey of the Middle Jurassic coal-bearing sequences in the Saishiteng coalfield, northern Qaidam Basin (NQB, a total of 20 rock types and 5 sedimentary facies were identified, including braided river, meandering river, braided delta, meandering river delta, and lacustrine facies. The distribution of rock types and sedimentary facies contributed to the reconstruction of three periods' sedimentary facies maps of the Middle Jurassic in the Saishiteng coalfield, namely, the Dameigou age, the early Shimengou age and the late Shimengou age. That also provided the basis for the development of a three-stage depositional model of the Middle Jurassic in the NQB, indicating the lacustrine basin of the NQB in the Dameigou age and early Shimengou age were corresponding to an overfill basin, and that in the late Shimengou age was related to a balanced-fill basin. The analysis of the stability and structure of coal seams based on sedimentary facies maps showed that the preferred coal-forming facies in the Saishiteng coalfield were inter-delta bay and interdistributary bay of lower delta plain in the Dameigou age. In particular, the swamps that developed on the subaqueous palaeohigh favored the development of thick coal seams. Thus, minable coal seams may also be found along the Pingtai palaeohigh in the western part of the Saishiteng coalfield.

Organic petrography:An approach for identification of maceral groups in Gheshlagh coal area, Eastern Alborz

Directory of Open Access Journals (Sweden)

Tahereh Rabani

2016-07-01

Full Text Available Introduction Maceral is a term to introduce organic components visible under a microscope (Stopes, 1935. The physical and chemical characteristics of macerals such as elemental composition, moisture content, hardness, density and petrographic characteristics differ. The differences in the physical and chemical characteristics of macerals are reflected in their industrial behavior.(Parkash, 1985. Petrographic analysis provides information on the various physical components of coals (Suwarna and Hemanto, 2007 and determination of quality of coal, coalification rate, composition and characteristics of coke and paleoenvironmental deposition (Taylor et al., 1998. Sampling and methodology Coal samples were collected from freshly mined coal from 11 coal seams of 4 active coal mines (Cheshlagh, Zemestan Yourt, Narges Chal and Cheshmehsaran for organic petrography in the Gheshlagh coal deposits. All samples were collected and stored in plastic bags to prevent contamination and weathering. Samples were prepared for microscopic analysis by reflected light following ASTM Standard procedure D2797-04. For microscopic study, coal samples were crushed to1-mm size fraction (18 mesh size, mounted in epoxy resin and polished. Three polished samples were prepared for each coal seam. The petrographic composition was obtained by maceral analyses under standard conditions (ISO 7404/3, 2009, for maceral analysis. Maceral point counting (based on 400 points analyses were performed using an Olympus BX51 reflected light microscope. The terminology used to identify and describe the organic matter particles is the one proposed by the International Committee for Coal and Organic Petrology (ICCP, 1998; ICCP, 2001; Scott and Glasspool, 2007; Taylor et al., 1998; Stach et al., 1982; Hower et al., 2009; Hower and Wagner, 2012. Organic petrography of theGheshlagh coal seams The vitrinite maceral group is dominant in all coal seams (66.2 to 87.2 vol.% and includes collodetrinite

Depositional conditions of the coal-bearing Hirka Formation beneath ...

Indian Academy of Sciences (India)

This work focuses on the relationship between the coal deposition and explosive volcanism of the Miocene basin, NW central Anatolia, Turkey. The coal-bearing Hirka Formation was deposited over the Galatian Andesitic Complex and/or massive lagoonal environments during the Miocene. The investigated lignite is a high ...

Experience with dust suppression in mining a thick, dirty seam

Energy Technology Data Exchange (ETDEWEB)

Siepmann, D; Kohlhauer, H

1975-11-20

Dust suppression measures used when mining a thick, dirty seam are described. Dust sprays inside and outside the shearer drum helped to reduce coarse dust, but the resulting increase in moisture content of the coal limits the extent to which this method can be used. The shields were also fitted with sprays. Because of the dirt in the seam, continuous, remotely controlled deep infusion was used. This reduced the dust concentration from more than 10 mg/m/sup 3/ to between 3.9 and 6.6 mg/m/sup 3/.

Assessing dynamics of ash content formation in coal at a working face in mines

Energy Technology Data Exchange (ETDEWEB)

Maidukov, G L; Lobkin, V M

1983-05-01

Factors which influence ash content in coal mined at a working face are analyzed: ash content in coal, stability of rock layers surrounding a coal seam, mechanical and physical properties of the direct roof. A mathematical model of ash content formation at a working face is described. On the basis of the model a computer program has been constructed. The program is used for calculating the mean value of ash content in coal and the standardized deviation. The program considers all causes of ash fluctuation in coal such as mining conditions, coal seam thickness, fluctuations in coal seam thickness, mechanical and physical properties of rocks surrounding a coal seam, particularly in the direct roof, mining systems, narrow or wide web shearer loaders, powered supports, hydraulic props, timber friction props with timber roof bars or with steel roof bars. A classification of rocks considering roof stability used by the program is described. A scheme of the program is given. Examples of using the program for forecasting ash content in coal and ash content fluctuations in Donbass mines are evaluated. (In Russian)

Study on Gas Drainage by Pressure Relief for Floor Through Beds Holes in Far Distance Lower Protective Coal Seam%远距离下保护层底板穿层钻孔卸压瓦斯抽采研究

Institute of Scientific and Technical Information of China (English)

刘军; 李生舟; 姚明柱

2017-01-01

This paper takes the remote lower protective layer 11# coal seam mining to protect main 3# coal seam as the research object in Songshuping Coal Mine.It is concluded that it is reasonable to arrange 3314 floor gas drainage roadway at the bottom 15 m of the 3# coal seam through arranging through beds grid format upholes in floor roadway to extract the protective layer and carry out pressure relief gas.The actual extraction data show that during the mining of the long-distance protective layer,the influence of the mining can effectively relieve the pressure and improve the permeability of the protective layer.The pre-pumping rate of the drainage area is about 65.6％.According to the effect analysis of pressure relief gas extraction,11# coal seam after the protection of the working layer in front of 10 m to the protective layer of the face of 60 m within the corresponding overlying 3# coal seam is the best pressure relief gas extraction area.%以桑树坪煤矿远距离下保护层11#煤层开采保护主采3#煤层为研究对象,利用底板巷布置上向穿层网格式钻孔抽采被保护层卸压瓦斯,研究得出将3314底板瓦斯抽放巷布置在3#煤层底部法距15 m处较为合理.实际抽采数据表明,在远距离下保护层开采期间,采动影响能够有效卸压,提高被保护层的透气性,底抽巷预抽区域瓦斯预抽率约为65.6％.从卸压瓦斯抽采效果分析,11#煤层回采后保护层工作面前方10m至保护层工作面后方60 m范围内对应的上覆3#煤层区域为最佳卸压瓦斯抽采区域.

Radioecological situation at the 'Karazhyra' coal deposit

International Nuclear Information System (INIS)

Panin, M.S.; Artamonova, E.N.; Medvedev, P.P.

2005-01-01

This paper presents results of the current radiological situation in ground water within the 'Karazhyra' coal deposit. The fulfilled studies have been revealed groundwater contamination with wide variety of anthropogenic radionuclides. Analysis of the current level of radionuclide activity in ground water of the coal deposit allows considering the radionuclides to be not hazardous. Results of many-year observations gave a possibility to quantitatively describe radionuclide content in ground water as well as predict development of water-bearing horizon radiation situation for the near future. (author)

Resistance seam welding

International Nuclear Information System (INIS)

Schueler, A.W.

1977-01-01

The advantages and disadvantages of the resistance seam welding process are presented. Types of seam welds, types of seam welding machines, seam welding power supplies, resistance seam welding parameters and seam welding characteristics of various metals

Operational and geotechnical constraints to coal mining in Alaska's interior

Energy Technology Data Exchange (ETDEWEB)

Corser, P; Usibelli, M

1989-01-01

Surface mining of coal from the Poker Flats mining area to the north of Healy, Alaska began in 1978. Current operations involve a 25 m/sup 3/ walking dragline which strips two coal seams, using an extended bench on the second pass; a fleet of trucks and shovels are used for coal removal and some limited overburden stripping. Geotechnical constraints to mining within the steeply dipping coal deposits are discussed. The area had a number of landslides. During 1984, mining operations close to a landslide caused movement to resume. A mine plan was developed which allowed the coal to be safely removed without inducing additional movement. This involves a dipline mining scheme through the slide area. Future mine plans will acknowledge the hazards of mining through potentially unstable zones. Aerial photographs, field mapping and geological exploration were used. 1 ref., 6 figs.

Comparative organic petrology of interlayered sandstones, siltstones, mudstones and coals in the Upper Carboniferous Ruhr basin, northwest Germany, and their thermal history and methane generation

Energy Technology Data Exchange (ETDEWEB)

Scheidt, G.; Littke, R. (Harress Geotechnik GmbH, Floersheim (Germany, F.R.))

1989-01-01

In the coal-mining Ruhr-area, Upper Carboniferous rocks consist of interlayered sandstones, siltstones, mudstones and coals. They were deposited in a tropical, paralic environment where alternating fluvial sedimentation, occasional marine ingressions, and swamp growth resulted in an irregular cyclic succession. The total sedimentary package contains on an average 6 Vol.% of organic manner. About 70 Vol. % of the organic matter occurs in coal seams, the rest as dispersed organic matter in clastic rocks. The organic matter is autochthonous in the coals and allochthonous in associated sandstones and siltstones. It consists of about 70% vitrinite, 20% inertinite, and 10% liptinite. The overall maceral group composition is the same for coals and dispersed organic matter. This surprising similarity is caused by a nearly exclusive input of land-plant derived organic matter to swamps and fluvial systems and a similar degree of preservation. Highest average liptinite contents were found in unrooted mudstones, highest average inertinite contents in coarse-grained siltstones and highest average vitrinite percentages in sandstones. Maturities of the sediments studied are well within the hydrocarbon generation window, e.g. vitrinite reflectivities range from 0.6% to 1.6%. Reflectivities measured on dispersed particles in clastic rocks are similar to those measured in coal seams. Calculations of the amount of methane generated indicate that coal seams contributed more to the total hydrocarbon generation than dispersed organic matter. 51 refs., 13 figs.

Introduction to South African coal mining and exploration

CSIR Research Space (South Africa)

Jeffrey, L

2015-01-01

Full Text Available , such as is mined at the No. 2 Mine at Kriel Colliery9. Klip River The Bottom Seam in the Klip River Coalfield (equivalent to the Gus Seam) is high in sulphur & phosphorus, with sulphur usually ranging from 1.3% to 1.8%1, 10. The Top Seam (corresponding... to the Alfred Seam) has a smaller bright coal proportion than the Bottom Seam1, but like the Bottom Seam, the rank of the Top Seam ranges from bituminous to anthracitic with generally high sulphur & phosphorus content. In general, the Klip River Coalfield...

BARZAS DEPOSIT SAPROPELITE COALS: PROSPECTS OF INTEGRATED DEVELOPMENT

Directory of Open Access Journals (Sweden)

L. V. Kuznetsova

2018-03-01

Full Text Available The urgency of the problem. Sapropelite coals of the Barzas deposit of Kuzbass are good raw materials for producing liquid fuel, lubricating oils, paraffin, etc. Apart from that, they are enriched with molybdenum, niobium, rubidium, yttrium and titanium. The content of these deposits is higher than the minimal content, which determines the industrial importance of coal as a source of ore raw materials. However, until now, the field is not being developed because of the economic inexpediency and the lack of a solution to the problem of recycling of incineration and semi-coking waste, which have high ash content and a large volume. The purpose of the study: to develop the concept of integrated development of the Barzas sapropelite coal deposit on the basis of creating efficient, environmentally friendly and low-waste production. Research methodology. The analysis of geological and mining conditions of the formation, which is called the Main, the results of its geochemical studies of existing technologies of mining and processing the high-ash solid fuels. The promising areas of their development were also considered. Cluster approach to the development of sapropelite coal deposits. Results. Coal mining at the sites with different geological conditions can be carried out with openly-underground mobile means of mechanization. The First mine field can be developed by the underground way on the development system called “Long poles along the strike”. This can be attained by means of the comprehensive mechanization of the Second mine field. Also, “Long poles along strike, take out the strips by the drop” are combined sections of a mechanized roof support with mobile means of cutting and transportation of coal – the Third mine field. The energy-chemical cluster of the Barzas deposit of sapropelite coals is a complex of the enterprises, which are technologically connected among them. They are concentrated on the same territory, which includes

FY 1998 basic survey for coal resource development. Data collection of the joint research of new technology in the geophysical exploration of coal resources (land area shallow seam survey); 1998 nendo sekitan shigen kaihatsu kiso chosa shiryoshu. Shintansa gijutsu chosa kaihatsu (rikuiki senso tansa)

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

This is a compilation of the data on the coal resource land area shallow seam survey conducted in FY 1998 as the basic survey for coal resource development. The trend survey was made from July 26 to August 6, 1998. The purposes of the survey are to study the image analysis method, examples of application of the reflection seismic survey to coal, and inversion technology. The data compilation includes the following: 1. Minutes of the proceedings of the FY 1998 Japan-Australia steering committee (in English). 2. Data/proceedings of the FY 1998 Japan-Australia technical study committee (in English). 3. Results of the GPS measurement of reflection seismic survey traverse lines in Caroona district. 4. List of parameters in the FY 1998 reflection seismic survey data processing. 5. Report on the work of inspection/repair of seismic pulse generator. 6. List of the data on diameter of the test boring conducted in FY 1998. 7. NEDO-DMR CAROONA DDH borehole core pictures. 8. Estimated curves. 9. Report on the trend survey of the FY 1998 coal resource development basic survey (land area shallow seam survey). 10. Pictures. 11. Data on the 1st (FY 1998) new exploration technology study committee. (NEDO)

Mercury stable isotope signatures of world coal deposits and historical coal combustion emissions.

Science.gov (United States)

Sun, Ruoyu; Sonke, Jeroen E; Heimbürger, Lars-Eric; Belkin, Harvey E; Liu, Guijian; Shome, Debasish; Cukrowska, Ewa; Liousse, Catherine; Pokrovsky, Oleg S; Streets, David G

2014-07-01

Mercury (Hg) emissions from coal combustion contribute approximately half of anthropogenic Hg emissions to the atmosphere. With the implementation of the first legally binding UNEP treaty aimed at reducing anthropogenic Hg emissions, the identification and traceability of Hg emissions from different countries/regions are critically important. Here, we present a comprehensive world coal Hg stable isotope database including 108 new coal samples from major coal-producing deposits in South Africa, China, Europe, India, Indonesia, Mongolia, former USSR, and the U.S. A 4.7‰ range in δ(202)Hg (-3.9 to 0.8‰) and a 1‰ range in Δ(199)Hg (-0.6 to 0.4‰) are observed. Fourteen (p coal Hg emissions tracing. A revised coal combustion Hg isotope fractionation model is presented, and suggests that gaseous elemental coal Hg emissions are enriched in the heavier Hg isotopes relative to oxidized forms of emitted Hg. The model explains to first order the published δ(202)Hg observations on near-field Hg deposition from a power plant and global scale atmospheric gaseous Hg. Yet, model uncertainties appear too large at present to permit straightforward Hg isotope source identification of atmospheric forms of Hg. Finally, global historical (1850-2008) coal Hg isotope emission curves were modeled and indicate modern-day mean δ(202)Hg and Δ(199)Hg values for bulk coal emissions of -1.2 ± 0.5‰ (1SD) and 0.05 ± 0.06‰ (1SD).

Fast and safe gas detection from underground coal fire by drone fly over

International Nuclear Information System (INIS)

Dunnington, Lucila; Nakagawa, Masami

2017-01-01

Underground coal fires start naturally or as a result of human activities. Besides burning away the important non-renewable energy resource and causing financial losses, burning coal seams emit carbon dioxide, carbon monoxide, sulfur oxide and methane, and is a leading cause of smog, acid rain, global warming, and air toxins. In the U.S. alone, the combined cost of coal-fire remediation projects that have been completed, budgeted, or projected by the U.S. Department of the Interior's Office of Surface Mining Remediation and Enforcement (OSM), exceeds $1 billion. It is estimated that these fires generate as much as 3% of the world's annual carbon dioxide emissions and consume as much as 5% of its minable coal. Considering the magnitude of environmental impact and economic loss caused by burning underground coal seams, we have developed a new, safe, reliable surface measurement of coal fire gases to assess the nature of underground coal fires. We use a drone mounted with gas sensors. Drone collected gas concentration data provides a safe alternative for evaluating the rank of a burning coal seam. In this study, a new method of determining coal rank by gas ratios is developed. Coal rank is valuable for defining parameters of a coal seam such as burn temperature, burn rate, and volume of burning seam. - Graphical abstract: Concluding Figure for Gas Ratios: Plotted points and ranges of adjusted literature data. Stars represent bituminous and subbituminous coal types; Ovals represent lignite. - Highlights: • Recognize underground coal fire as a potential source of energy. • Developed a creative, safe, reliable and fast gas detection method. • Developed a concept of gas ratio measurement method that can provide more accurate description of underground burning coal resource.

Forecast and Prevention of Coal and Gas Outbursts in the Case of Application of a New Mining Method - Drilling of a Coal Pillar

Directory of Open Access Journals (Sweden)

Vlastimil Hudeček

2010-10-01

Full Text Available Coal and gas outbursts are one of risk factors accompanying the mining of coal in low seams in the Ostrava-Karviná Coalfield.At the use of the method of longwall mining, all coal reserves have not been mined out owing to tectonic faults. For mining outthe residual reserves, the application of a new mining method - drilling of a coal pillar was proposed.The method of mining of a coal seam utilizing long large diameter boreholes is verified in the Paskov Mine (company OKD, JSC –Czech Republic under conditions of rock mass with hazard of rock and gas outbursts in localities of residual pillars left in seams afterfinishing the mining operations performed with using the classical method of longwall working along the strike. [5]Forecast and preventive measures applied to the verification of the new method were based on previous experience withthe mining of seams with hazard of coal and gas outbursts. They accepted fully valid legislation, i.e. Ordinance of Ostrava RegionalMining Authority No. 3895/2002 and supplementary materials (Instructions and Guidelines. The proposed measures respectedthe character of the method being verified. [4]For all areas being mined, projects containing also chapters specifying the problems of ensuring the safety of mining worksand operation under conditions of hazard of coal and gas outbursts were prepared.In the contributions, basic proposals for the principles of coal and gas outburst forecast and prevention when applying the newmining method – drilling of a coal pillar are presented

Coal Field Fire Fighting - Practiced methods, strategies and tactics

Science.gov (United States)

Wündrich, T.; Korten, A. A.; Barth, U. H.

2009-04-01

Subsurface coal fires destroy millions of tons of coal each year, have an immense impact to the ecological surrounding and threaten further coal reservoirs. Due to enormous dimensions a coal seam fire can develop, high operational expenses are needed. As part of the Sino-German coal fire research initiative "Innovative technologies for exploration, extinction and monitoring of coal fires in Northern China" the research team of University of Wuppertal (BUW) focuses on fire extinction strategies and tactics as well as aspects of environmental and health safety. Besides the choice and the correct application of different extinction techniques further factors are essential for the successful extinction. Appropriate tactics, well trained and protected personnel and the choice of the best fitting extinguishing agents are necessary for the successful extinction of a coal seam fire. The chosen strategy for an extinction campaign is generally determined by urgency and importance. It may depend on national objectives and concepts of coal conservation, on environmental protection (e.g. commitment to green house gases (GHG) reductions), national funding and resources for fire fighting (e.g. personnel, infrastructure, vehicles, water pipelines); and computer-aided models and simulations of coal fire development from self ignition to extinction. In order to devise an optimal fire fighting strategy, "aims of protection" have to be defined in a first step. These may be: - directly affected coal seams; - neighboring seams and coalfields; - GHG emissions into the atmosphere; - Returns on investments (costs of fire fighting compared to value of saved coal). In a further step, it is imperative to decide whether the budget shall define the results, or the results define the budget; i.e. whether there are fixed objectives for the mission that will dictate the overall budget, or whether the limited resources available shall set the scope within which the best possible results shall be

Analysis and mapping of post-fire hydrologic hazards for the 2002 Hayman, Coal Seam, and Missionary Ridge wildfires, Colorado

Science.gov (United States)

Elliott, J.G.; Smith, M.E.; Friedel, M.J.; Stevens, M.R.; Bossong, C.R.; Litke, D.W.; Parker, R.S.; Costello, C.; Wagner, J.; Char, S.J.; Bauer, M.A.; Wilds, S.R.

2005-01-01

Wildfires caused extreme changes in the hydrologic, hydraulic, and geomorphologic characteristics of many Colorado drainage basins in the summer of 2002. Detailed assessments were made of the short-term effects of three wildfires on burned and adjacent unburned parts of drainage basins. These were the Hayman, Coal Seam, and Missionary Ridge wildfires. Longer term runoff characteristics that reflect post-fire drainage basin recovery expected to develop over a period of several years also were analyzed for two affected stream reaches: the South Platte River between Deckers and Trumbull, and Mitchell Creek in Glenwood Springs. The 10-, 50-, 100-, and 500-year flood-plain boundaries and water-surface profiles were computed in a detailed hydraulic study of the Deckers-to-Trumbull reach. The Hayman wildfire burned approximately 138,000 acres (216 square miles) in granitic terrain near Denver, and the predominant potential hazard in this area is flooding by sediment-laden water along the large tributaries to and the main stem of the South Platte River. The Coal Seam wildfire burned approximately 12,200 acres (19.1 square miles) near Glenwood Springs, and the Missionary Ridge wildfire burned approximately 70,500 acres (110 square miles) near Durango, both in areas underlain by marine shales where the predominant potential hazard is debris-flow inundation of low-lying areas. Hydrographs and peak discharges for pre-burn and post-burn scenarios were computed for each drainage basin and tributary subbasin by using rainfall-runoff models because streamflow data for most tributary subbasins were not available. An objective rainfall-runoff model calibration method based on nonlinear regression and referred to as the ?objective calibration method? was developed and applied to rainfall-runoff models for three burned areas. The HEC-1 rainfall-runoff model was used to simulate the pre-burn rainfall-runoff processes in response to the 100-year storm, and HEC-HMS was used for runoff

Coal-bed methane water effects on dill and essential oils

Science.gov (United States)

Pumping water from coal seams decreases the pressure in the seam and in turn releases trapped methane; this is the most common and economic way of methane extraction. The water that is pumped out is known as coal-bed methane water (CBMW), which is high in sodium and other salts. In past 25 years, th...

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.

Rock burst prevention at steep seam mining

Energy Technology Data Exchange (ETDEWEB)

Efremov, G D

1988-09-01

At steep shield longwalls one method of preventing rock bursts is to avoid sharp angles during working. Stress in coal and rock body that appears when steep seams are worked where rock bursts occur at corners of set-up entries is discussed. The dynamic interaction between gas and rock pressure is assessed. Maintains that in order to avoid rock bursts at these places it is necessary to turn the protruding coal wall by 20-30 degrees towards the coal body to divert the action of shift forces. At the same time the face should also be inclined (by 10-15 degrees) to move the zones of increased stress away from the corner into the coal and rock body. Stress at workings with round cross-sections is 3-4 times lower than at square cross-sections. Recommendations are given that concern shearer loader operation (semi-spherical shape of the face), borehole drilling and water injection. Initial distance of 10-15 m between boreholes is suggested. 3 refs.

Exploitation of the in-seam miner and operational experience

Energy Technology Data Exchange (ETDEWEB)

Wilson, W I.S.; Morris, A H

1977-12-01

The In-seam Miner started as an investigatory project at MRDE in 1969. Since that time it has passed through the classic development stages of design of prototype, surface trials, underground trials, modification, production of more machines, assessment of experience and then wider exploitation. At the present time well over 100 machines have been supplied to the National Coal Board. The original machine was hydraulically driven and all but five of the machines supplied to date are of this type. The variety of applications that the machine has found in the mining industry has caused derivative development to embrace machines of length varying from 12-ft centers to 44-ft centers, to work in seams ranging from 40 in. up to 68 in. The range of applications has included face drivages, stablehole operations, in-seam retreat roadways and dirt-absorbing headings. Five electrically driven machines are now coming onto the market and experience with them, though limited, is very encouraging. The paper concentrates on two major aspects of the overall development process: first, the management of exploitation; and second, some operational experience of the In-seam Miner in South Midlands area.

Empirical prediction of ash deposition propensities in coal-fired utilities

Energy Technology Data Exchange (ETDEWEB)

Frandsen, F.

1997-01-01

This report contain an outline of some of the ash chemistry indices utilized in the EPREDEPO (Empirical PREdiction of DEPOsition) PC-program, version 1.0 (DEPO10), developed by Flemming Frandsen, The CHEC Research Programme, at the Department of Chemical Engineering, Technical University of Denmark. DEPO10 is a 1st generation FTN77 Fortran PC-programme designed to empirically predict ash deposition propensities in coal-fired utility boilers. Expectational data (empirical basis) from an EPRI-sponsored survey of ash deposition experiences at coal-fired utility boilers, performed by Battelle, have been tested for use on Danish coal chemistry - boiler operational conditions, in this study. (au) 31 refs.

Application of fractal theory to top-coal caving

International Nuclear Information System (INIS)

Xie, H.; Zhou, H.W.

2008-01-01

The experiences of underground coal mining in China show that coal in a thick hard coal seam with a hard roof, the so-called 'double hard coal seam', is difficult to be excavated by top-coal caving technique. In order to solve the problem, a top-coal weakening technique is proposed in this paper. In the present study, fractal geometry provides a new description of the fracture mechanism for blasting. By means of theoretical analysis of the relationship between the fractal dimension of blasting fragments and the dynamite specific energy, a mechanical model for describing the size distribution of top-coal and the dissipation of blasting energy is proposed. The theoretical results are in agreement with laboratory and in situ test results. Moreover, it is shown that the fractal dimension of coal fragments can be used as an index for optimizing the blasting parameters for a top-coal weakening technique

Width design for gobs and isolated coal pillars based on overall burst-instability prevention in coal mines

Directory of Open Access Journals (Sweden)

Junfei Zhang

2016-08-01

Full Text Available An investigation was conducted on the overall burst-instability of isolated coal pillars by means of the possibility index diagnosis method (PIDM. First, the abutment pressure calculation model of the gob in side direction was established to derive the abutment pressure distribution curve of the isolated coal pillar. Second, the overall burst-instability ratio of the isolated coal pillars was defined. Finally, the PIDM was utilized to judge the possibility of overall burst-instability and recoverability of isolated coal pillars. The results show that an overall burst-instability may occur due to a large gob width or a small pillar width. If the width of the isolated coal pillar is not large enough, the shallow coal seam will be damaged at first, and then the high abutment pressure will be transferred to the deep coal seam, which may cause an overall burst-instability accident. This approach can be adopted to design widths of gobs and isolated coal pillars and to evaluate whether an existing isolated coal pillar is recoverable in skip-mining mines.

Formation and retention of methane in coal

Energy Technology Data Exchange (ETDEWEB)

Hucka, V.J.; Bodily, D.M.; Huang, H.

1992-05-15

The formation and retention of methane in coalbeds was studied for ten Utah coal samples, one Colorado coal sample and eight coal samples from the Argonne Premium Coal Sample Bank.Methane gas content of the Utah and Colorado coals varied from zero to 9 cm{sup 3}/g. The Utah coals were all high volatile bituminous coals. The Colorado coal was a gassy medium volatile bituminous coal. The Argonne coals cover a range or rank from lignite to low volatile bituminous coal and were used to determine the effect of rank in laboratory studies. The methane content of six selected Utah coal seams and the Colorado coal seam was measured in situ using a special sample collection device and a bubble desorbometer. Coal samples were collected at each measurement site for laboratory analysis. The cleat and joint system was evaluated for the coal and surrounding rocks and geological conditions were noted. Permeability measurements were performed on selected samples and all samples were analyzed for proximate and ultimate analysis, petrographic analysis, {sup 13}C NMR dipolar-dephasing spectroscopy, and density analysis. The observed methane adsorption behavior was correlated with the chemical structure and physical properties of the coals.

Groundwater and underground coal gasification in Alberta

International Nuclear Information System (INIS)

Haluszka, A.; MacMillan, G.; Maev, S.

2010-01-01

Underground coal gasification has potential in Alberta. This presentation provided background information on underground coal gasification and discussed groundwater and the Laurus Energy demonstration project. A multi-disciplined approach to project assessment was described with particular reference to geologic and hydrogeologic setting; geologic mapping; and a hydrogeologic numerical model. Underground coal gasification involves the conversion of coal into synthesis gas or syngas. It can be applied to mined coal at the surface or applied to non-mined coal seams using injection and production wells. Underground coal gasification can effect groundwater as the rate of water influx into the coal seams influences the quality and composition of the syngas. Byproducts created include heat as well as water with dissolved concentrations of ammonia, phenols, salts, polyaromatic hydrocarbons, and liquid organic products from the pyrolysis of coal. A process overview of underground coal gasification was also illustrated. It was concluded that underground coal gasification has the potential in Alberta and risks to groundwater could be minimized by a properly designed project. refs., figs.

Zulia rich coal seams to fuel Venezuela

Energy Technology Data Exchange (ETDEWEB)

1983-06-16

In March, 1982, Carbozulia awarded a contract to Fluor Corp. to provide basic engineering services, including mine planning and geology, for the two-phase project. The open pit mine and ancillary facilities, valued at more than $200 million, will provide steam and metallurgical coal for domestic use. The site, Mina Paso Diablo, is located about 60 miles northwest of Maracaibo. Upon phase one completion sometime in 1987, the mill will start production, gradually increasing to 4 million metric-tons-per-year. This will increase to 6.4 million metric tons when phase two is completed. In addition to the mine, the Venezuelan government plans to build an industrial complex along Lake Maracaibo. Corpozulia will build a steel-rolling mill and add a 350,000 metric tons-per-year coking oven, which will consume about 7% of the mine's metallurgical-coal production. Another government-owned firm, Electric Energy of Venezuela, plans to build a thermo-electric plant nearby. Two 250-megawatt units are planned initially, with potential to add another six units. At full capacity, the plant will burn more than 90% of the coal produced from the mine. Mina Paso Diablo contains one of Latin America's largest proven coal reserves - about 350 million metric tons - with guesstimates running as high as 4 billion metric tons for the Zulia coal basin. The coal is of superior quality, running about 12,000 to 13,000 Btu's per lb. with a low ash and sulphur content.

The coal cleat system: A new approach to its study

Directory of Open Access Journals (Sweden)

C.F. Rodrigues

2014-06-01

Full Text Available After a general analysis regarding the concept of coal “cleat system”, its genetic origin and practical applications to coalbed methane (CBM commercial production and to CO2 geological sequestration projects, the authors have developed a method to answer, quickly and accurately in accordance with the industrial practice and needs, the following yet unanswered questions: (1 how to define the spatial orientation of the different classes of cleats presented in a coal seam and (2 how to determine the frequency of their connectivites. The new available and presented techniques to answer these questions have a strong computer based tool (geographic information system, GIS, able to build a complete georeferentiated database, which will allow to three-dimensionally locate the laboratory samples in the coalfield. It will also allow to better understand the coal cleat system and consequently to recognize the best pathways to gas flow through the coal seam. Such knowledge is considered crucial for understanding what is likely to be the most efficient opening of cleat network, then allowing the injection with the right spatial orientation, of pressurized fluids in order to directly drain the maximum amount of gas flow to a CBM exploitation well. The method is also applicable to the CO2 geological sequestration technologies and operations corresponding to the injection of CO2 sequestered from industrial plants in coal seams of abandoned coal mines or deep coal seams.

Study of Coal Burst Source Locations in the Velenje Colliery

Directory of Open Access Journals (Sweden)

Goran Vižintin

2016-06-01

Full Text Available The Velenje coal mine (VCM is situated on the largest Slovenian coal deposit and in one of the thickest layers of coal known in the world. The thickness of the coal layer causes problems for the efficiency of extraction, since the majority of mining operations is within the coal layer. The selected longwall coal mining method with specific geometry, increasing depth of excavations, changes in stress state and naturally given geomechanical properties of rocks induce seismic events. Induced seismic events can be caused by caving processes, blasting or bursts of coal or the surrounding rock. For 2.5D visualization, data of excavations, ash content and calorific value of coal samples, hanging wall and footwall occurrence, subsidence of the surface and coal burst source locations were collected. Data and interpolation methods available in software package Surfer®12 were statistically analyzed and a Kriging (KRG interpolation method was chosen. As a result 2.5D visualizations of coal bursts source locations with geomechanical properties of coal samples taken at different depth in the coal seam in the VCM were made with data-visualization packages Surfer®12 and Voxler®3.

Development of world coal reserves, their registration and their utilization

Energy Technology Data Exchange (ETDEWEB)

Bachmann, H

1979-10-01

This paper examines statistics on world coal production and world coal reserves with figures from 1860 to 1974 provided in tables and graphs. Eighty percent of the total world coal reserves (92% of world brown coal reserves) lie in the USA and USSR. The recent increase in total coal reserve estimates is due to exploration in western USA and in the USSR east of the Urals. Depth and thickness of the world's coal seams are shown in graphs and variations in coal quality are discussed. Problems associated with the anticipated substantial increase in coal production up to the year 2000 are considered. Encouraging higher coal production is the successful development of highly mechanized underground mining techniques and highly productive heavy surface mining equipment which allows excavation at increased depths. Surface mining is expected to make up 50% of total world mining operations in the near future. More complete deposit exploitation also contributes to higher coal production. Low international ship freight rates would facilitate future world coal trade. Obstacles are seen as: high, long term investments due to the fact that coal reserves lie far from populated and industrialized areas; opening new mines; transportation costs and infrastructure development.

复杂瓦斯地质条件下煤层透气性评价及抽采对策研究%Study on coal seam gas permeability evaluation and drainage countermeasures in complex gas geological conditions

Institute of Scientific and Technical Information of China (English)

易汉华

2017-01-01

针对煤层瓦斯地质条件复杂的米箩煤矿在生产过程中瓦斯抽采难、预抽时间长、矿区范围内可采煤层透气性不确定的问题,采用煤层透气性系数现场测定的方法,对米箩煤矿1号、3号、9号、10号、16号、26号、27号、29号、31号和40号煤层施工测压钻孔进行了煤层透气性系数相关参数的测定,并依据钻孔径向流量法计算公式,对米箩煤矿各煤层透气性系数进行了评价,得出了米箩煤矿矿区范围内1号、3号、9号、10号、16号、26号、27号、29号、31号和40号煤层均为低透气性煤层.通过优化瓦斯抽采钻孔直径和钻孔间距的方式,改善了煤层透气性,并在1108底板瓦斯抽放巷两侧每隔15 m分别增设一个高位钻场,在钻场内向3号煤层布置19个斜向穿层抽采钻孔,有效缩短了110310回采工作面瓦斯预抽时间.%The geological conditions of Miluo Coal Mine is complex,in the production process,gas is difficult to drain,the time of gas drainage is long,and permeability of minable seam was uncertain,aimed at these problems,the permeability coefficient measuring on site was applied,thus,pressure drilling were constructed in No.1,3,9,10,16,26,27,29,31 and No.40 coal seam,whose purpose was to evaluate the permeability coefficient of coal seams.It was proposed that No.1,3,9,10,16,26,27,29,31 and No.40 are of low permeability coal seam.Through the optimization of diameter and spacing of holes for gas drainage,the permeability of coal seam was improved,high-level drilling field was added on two side of 1108 floor drainage roadway,and the spacing of drilling field was 15 m.19 oblique layer-through boreholes were laid out into No.3 coal seam in the drilling field,and this has effectively reduced the pre-pumping time of the gas on 110310 working face.

Paleocene coal deposits of the Wilcox group, central Texas

Science.gov (United States)

Hook, Robert W.; Warwick, Peter D.; SanFilipo, John R.; Schultz, Adam C.; Nichols, Douglas J.; Swanson, Sharon M.; Warwick, Peter D.; Karlsen, Alexander K.; Merrill, Matthew D.; Valentine, Brett J.

2011-01-01

Coal deposits in the Wilcox Group of central Texas have been regarded as the richest coal resources in the Gulf Coastal Plain. Although minable coal beds appear to be less numerous and generally higher in sulfur content (1 percent average, as-received basis; table 1) than Wilcox coal deposits in the Northeast Texas and Louisiana Sabine assessment areas (0.5 and 0.6 percent sulfur, respectively; table 1), net coal thickness in coal zones in central Texas is up to 32 ft thick and more persistent along strike (up to 15 mi) at or near the surface than coals of any other Gulf Coast assessment area. The rank of the coal beds in central Texas is generally lignite (table 1), but some coal ranks as great as subbituminous C have been reported (Mukhopadhyay, 1989). The outcrop of the Wilcox Group in central Texas strikes northeast, extends for approximately 140 mi between the Trinity and Colorado Rivers, and covers parts of Bastrop, Falls, Freestone, Lee, Leon, Limestone, Milam, Navarro, Robertson, and Williamson Counties (Figure 1). Three formations, in ascending order, the Hooper, Simsboro, and Calvert Bluff, are recognized in central Texas (Figure 2). The Wilcox Group is underlain conformably by the Midway Group, a mudstone-dominated marine sequence, and is overlain and scoured locally by the Carrizo Sand, a fluvial unit at the base of the Claiborne Group.

Forecast fire damp emission in thin, steep coal bed; Prevision de Desprendimiento de Grisu en Capas Estrechas e Inclindas

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-12-31

A model to forecast fire damp emission in thin, steep coal bed, mining in advance and backfill works, has been developed and validated. The model estimates the amount of methane released towards the works, including fire damp proceeding from the actually mined seam, as well as methane coming from adjacent seams layers, depending on easy-to find parameters. Methane coming from the mined seam is determined as a function of the methane concentration in the seam and methane from adjacent seams is assessed by the degassification degree. This parameter depends also on the distance to the mined seam. The influence volume of a thin, steep mined coal bed has been determined, in order to study which seams and layers release methane towards the works. The works to develop the methane emission model were done in a coal face on Maria seam, in San Antonio mine, belonging to HUNOSA. The validation works were carried out in 24 left south seam, in the belonging to Minas de Figaredo, S. A. (Author)

Modeling of carbon sequestration in coal-beds: A variable saturated simulation

International Nuclear Information System (INIS)

Liu Guoxiang; Smirnov, Andrei V.

2008-01-01

Storage of carbon dioxide in deep coal seams is a profitable method to reduce the concentration of green house gases in the atmosphere while the methane as a byproduct can be extracted during carbon dioxide injection into the coal seam. In this procedure, the key element is to keep carbon dioxide in the coal seam without escaping for a long term. It is depended on many factors such as properties of coal basin, fracture state, phase equilibrium, etc., especially the porosity, permeability and saturation of the coal seam. In this paper, a variable saturation model was developed to predict the capacity of carbon dioxide sequestration and coal-bed methane recovery. This variable saturation model can be used to track the saturation variability with the partial pressures change caused by carbon dioxide injection. Saturation variability is a key factor to predict the capacity of carbon dioxide storage and methane recovery. Based on this variable saturation model, a set of related variables including capillary pressure, relative permeability, porosity, coupled adsorption model, concentration and temperature equations were solved. From results of the simulation, historical data agree with the variable saturation model as well as the adsorption model constructed by Langmuir equations. The Appalachian basin, as an example, modeled the carbon dioxide sequestration in this paper. The results of the study and the developed models can provide the projections for the CO 2 sequestration and methane recovery in coal-beds within different regional specifics

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

OpenAIRE

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

2016-01-01

Using a comprehensive data set (dissolved CH4, ?13C-CH4, ?2H-CH4, ?13C-DIC, ?37Cl, ?2H-H2O, ?18O-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. ?13C-CH4 data in the gas reservoir (?58? to ?49?) and sha...

Coal depositional models in some tertiary and cretaceous coal fields in the US western interior

Energy Technology Data Exchange (ETDEWEB)

Flores, R M

1979-12-01

Detailed stratigraphic and sedimentological studies of the Tertiary Tongue River Member of the Fort Union Formation in the Powder River Basin, Wyoming, and the Cretaceous Blackhawk Formation and Star Point Sandstone in the Wasatch Plateau, Utah, indicate that the depositional environments of coal played a major role in controlling coal thickness, lateral continuity, potential minability, and type of floor and roof rocks. The potentially minable, thick coal beds of the Tongue River Member were primarily formed in long-lived floodbasin backswamps of upper alluvial plain environment. Avulsion of meandering fluvial channels contributed to the erratic lateral extent of coals in this environment. Laterally extensive coals formed in floodbasin backswamps of a lower alluvial plain environment; however, interruption by overbank and crevasse-splay sedimentation produced highly split and merging coal beds. Lacustrine sedimentation common to the lower alluvial plain, similar to the lake-covered lower alluvial valley of the Atchafalaya River Basin, is related to a high-constructive delta. In contrast to these alluvial coals are the deltaic coal deposits of the Blackhawk Formation. The formation consists of three coal populations: upper delta plain, lower delta plain, and back-barrier. Coals of the lower delta plain are thick and laterally extensive, in contrast to those of the upper delta plain and back-barrier, which contain abundant, very thin and laterally discontinuous carbonaceous shale partings. The reworking of the delta-front sediments of the Star Point Sandstone suggests that the Blackhawk-Star Point delta was a high-destructive system. 1 figure, 1 table.

Preliminary Result of Geophysical Some Studieson the Nariinsukhait Coal Deposit

Science.gov (United States)

Norov, B.; Purevjav, N.; Roy, D. K., Sr.

2017-12-01

Nariinsukhait coal deposit has a strategic importance on Mongolian national economic development. The deposit is located in Gurvan-tes of the Umnu-gobi province, as 849 km south-west away from Ulaanbaatar. The deposit in geographically, belongs to Gobi Altai region region of the Altai mountain region. The area contains Permian, Cretaceous, Jurassic, Triassic age of sediments. Sediments are red or sedimentary cover on some part of area (Minjin. Ch., Batnyam. D., Rentsendorj. S (Baatarkhuyag. A., Altantsetseg. D., 2015). The coal deposit is located in the center portion of the Nariinsukhait basin. The age of coal hosted sedimentary rock is Jurassic estimated by Paleo-botanic methodology, using examination of a total 59 kind of plants, 288 pollen grains (Baatarkhuyag. A., Altantsetseg. D., 2015). The thickness of coal hosted sedimentary sequence is approximately 1105.5m and named as Orgilohbulag formation. In case of geophysical exploration, preliminary interpretation of the coal basin has been done by 3 geophysical methodologies which commonly applying during exploration stage of coal. The interpretations are given below. Natural Gamma Sonde /NGRS 4140/: use to determine natural gamma activation on rock by radionuclides content (238U; 235U; 232Th; 40K). During measurements well contrasted coal bedding and, value indicate between 0-15cps. And depending on the rock type it has been changed, in case of siltstone, argillite, conglomerate value fluctuated between 15-40cps. However, those rocks natural gamma values are difference little, therefore not showing much contrast between rock types. Formation Density Sonde Version B /FDSB 4036/: The Nariinsukhait coal deposit Open holes and protective pipes of density is 0.5-1.5 g/cm3, 1.2-2.3 g/cm3 respectively. Not well contrasted during measurement due to some of sedimentary rock density range is so low as such sandstone, siltstone, and conglomerate. Therefore, applied resistivity methodology and done interpretation. DLL3

COAL-FIRED UTILITY BOILERS: SOLVING ASH DEPOSITION PROBLEMS; TOPICAL

International Nuclear Information System (INIS)

Christopher J. Zygarlicke; Donald P. McCollor; Steven A. Benson; Jay R. Gunderson

2001-01-01

The accumulation of slagging and fouling ash deposits in utility boilers has been a source of aggravation for coal-fired boiler operators for over a century. Many new developments in analytical, modeling, and combustion testing methods in the past 20 years have made it possible to identify root causes of ash deposition. A concise and comprehensive guidelines document has been assembled for solving ash deposition as related to coal-fired utility boilers. While this report accurately captures the current state of knowledge in ash deposition, note that substantial research and development is under way to more completely understand and mitigate slagging and fouling. Thus, while comprehensive, this document carries the title ''interim,'' with the idea that future work will provide additional insight. Primary target audiences include utility operators and engineers who face plant inefficiencies and significant operational and maintenance costs that are associated with ash deposition problems. Pulverized and cyclone-fired coal boilers are addressed specifically, although many of the diagnostics and solutions apply to other boiler types. Logic diagrams, ash deposit types, and boiler symptoms of ash deposition are used to aid the user in identifying an ash deposition problem, diagnosing and verifying root causes, determining remedial measures to alleviate or eliminate the problem, and then monitoring the situation to verify that the problem has been solved. In addition to a step-by-step method for identifying and remediating ash deposition problems, this guideline document (Appendix A) provides descriptions of analytical techniques for diagnostic testing and gives extensive fundamental and practical literature references and addresses of organizations that can provide help in alleviating ash deposition problems

Economic evaluation of coal deposits. Ekonomicheskaya otsenka ugolinykh mestorozhdenii

Energy Technology Data Exchange (ETDEWEB)

Raikhel' , B L

1979-01-01

A presentation is made of theoretical problems, methods, and criteria for the economic evaluation of coal deposits. An examination is made of factors which influence the formation of magnitudes that are utilized in economic evaluations as well as problems whose solution requires the consideration of the economic evaluation of coal deposits (evaluation of useful mineral losses, substantiation for the extraction of reserves under various conditions, sectioning off reserves to an operating mine, the completeness of reserve extraction, and technico-economic substantiation for quality). Extensive experience in planning is summarized and data are illustrated by examples. The book is intended for engineering-technical personnel of enterprises, organizations, planning, and scientific-research institutes of the coal industry as well as geological organizations. 29 references, 27 tables.

Formation and retention of methane in coal. Final report

Energy Technology Data Exchange (ETDEWEB)

Hucka, V.J.; Bodily, D.M.; Huang, H.

1992-05-15

The formation and retention of methane in coalbeds was studied for ten Utah coal samples, one Colorado coal sample and eight coal samples from the Argonne Premium Coal Sample Bank.Methane gas content of the Utah and Colorado coals varied from zero to 9 cm{sup 3}/g. The Utah coals were all high volatile bituminous coals. The Colorado coal was a gassy medium volatile bituminous coal. The Argonne coals cover a range or rank from lignite to low volatile bituminous coal and were used to determine the effect of rank in laboratory studies. The methane content of six selected Utah coal seams and the Colorado coal seam was measured in situ using a special sample collection device and a bubble desorbometer. Coal samples were collected at each measurement site for laboratory analysis. The cleat and joint system was evaluated for the coal and surrounding rocks and geological conditions were noted. Permeability measurements were performed on selected samples and all samples were analyzed for proximate and ultimate analysis, petrographic analysis, {sup 13}C NMR dipolar-dephasing spectroscopy, and density analysis. The observed methane adsorption behavior was correlated with the chemical structure and physical properties of the coals.

Quality of Coal in the Deposit Kongora - Tomislavgrad

International Nuclear Information System (INIS)

Zivkovic, S.; Nuic, J.; Krasic, D.

1998-01-01

The document accepted in Kyoto, signed by the republic of Croatia, oblige the signatory countries in view of the Agreement on reducing emissions of noxious gases. These obligations burden the development of the energy sector by high technological requirements which will make energy even more expensive. The basic part of the energy system constitute fossil fuel driven thermal power plants (presently found less hazardous than the nuclear option). The commitment of the republic of Croatia to build up a basic thermal energy system in the years to come has initiated a series of discussions on energy sources, i.e. on the choice of fossil fuels. Possibilities have been studied as regards the import of gas (Siberia, Algeria), coal (Australia, the USA, Colombia, etc.), while at the same time neglecting the resources in immediate vicinity. Major coal deposits in the Dalmatian hinterland (Bosnia and Herzegovina), 70km from the Adriatic coast, deserve the attention of experts and scientists in surveying energy potential, particularly as it is a question of the low caloric value coal with scant sulphur (under 1 percent). So far the experiences are favourable and point to the coal deposit Kongora as a possible energy potential. (author)

Microbial diversity of western Canadian subsurface coal beds and methanogenic coal enrichment cultures

Energy Technology Data Exchange (ETDEWEB)

Penner, Tara J.; Foght, Julia M. [Department of Biological Sciences, University of Alberta, Edmonton, Alberta (Canada); Budwill, Karen [Carbon and Energy Management, Alberta Innovates-Technology Futures, 250 Karl Clark Road, Edmonton, Alberta (Canada)

2010-05-01

Coalbed methane is an unconventional fuel source associated with certain coal seams. Biogenic methane can comprise a significant portion of the gas found in coal seams, yet the role of microbes in methanogenesis in situ is uncertain. The purpose of this study was to detect and identify major bacterial and archaeal species associated with coal sampled from sub-bituminous methane-producing coal beds in western Canada, and to examine the potential for methane biogenesis from coal. Enrichment cultures of coal samples were established to determine how nutrient amendment influenced the microbial community and methane production in the laboratory. 16S rRNA gene clone libraries were constructed using DNA extracted and amplified from uncultured coal samples and from methanogenic coal enrichment cultures. Libraries were screened using restriction fragment length polymorphism, and representative clones were sequenced. Most (> 50%) of the bacterial sequences amplified from uncultured coal samples were affiliated with Proteobacteria that exhibit nitrate reduction, nitrogen fixation and/or hydrogen utilization activities, including Pseudomonas, Thauera and Acidovorax spp., whereas enrichment cultures were dominated by Bacteroidetes, Clostridia and/or Lactobacillales. Archaeal 16S rRNA genes could not be amplified from uncultured coal, suggesting that methanogens are present in coal below the detection levels of our methods. However, enrichment cultures established with coal inocula produced significant volumes of methane and the archaeal clone libraries were dominated by sequences closely affiliated with Methanosarcina spp. Enrichment cultures incubated with coal plus organic nutrients produced more methane than either nutrient or coal supplements alone, implying that competent methanogenic consortia exist in coal beds but that nutrient limitations restrict their activity in situ. This report adds to the scant literature on coal bed microbiology and suggests how microbes may be

Fouling deposition characteristic by variation of coal particle size and deposition temperature in DTF (Drop Tube Furnace)

Energy Technology Data Exchange (ETDEWEB)

Namkung, Hueon; Jeon, Youngshin; Kim, Hyungtaek [Ajou Univ., Suwon (Korea, Republic of). Div. of Energy Systems Research; Xu, Li-hua [IAE, Suwon (Korea, Republic of). Plant Engineering Center

2013-07-01

One of the major operation obstacles in gasification process is ash deposition phenomenon. In this investigation, experiment was carried out to examine coal fouling characteristics using a laminar DTF (Drop Tube Furnace) with variation of operating condition such as different coal size, and probe surface temperature. Four different samples of pulverized coal were injected into DTF under various conditions. The ash particles are deposited on probe by impacting and agglomerating action. Fouling grains are made of eutectic compound, which is made by reacting with acid minerals and alkali minerals, in EPMA (Electron Probe Micro-Analysis). And agglomeration area of fouling at top layer is wide more than it of middle and bottom layer. The major mineral factors of fouling phenomenon are Fe, Ca, and Mg. The deposition quantity of fouling increases with increasing particle size, high alkali mineral (Fe, Ca, and Mg) contents, and ash deposition temperature.

Specific Energy of Hard Coal Under Load

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Bogusz Anna

2015-03-01

Full Text Available The article presents results of experimental tests of energy parameters of hard coals under loading, collected from research sites located within five main geologic structures of Upper Silesian Coal Basin (GZW - Main Trough, Main Anticline, Bytom Trough, Rybnik Trough and Chwałowice Trough. Coals from12 mines were analysed, starting with seams of group 200, through groups 400, 500, 600 and, finally, seams of group 700. Coal of each of the groups of seams underwent uniaxial compression stress of the energy parameters, in a servo-controlled testing machine MTS-810NEW, for the full range of strain of the tested coal samples. Based on the tests the dependence of different types of specific energy of longitudinal strain of coals on the value of uniaxial compression strength was determined. The dependence of the value of dissipated energy and kinetic energy of coals on the uniaxial compression strength was described with a linear function, both for coals which due to their age belong to various bed sand for various lithotypes of coal. An increase in the value of dissipated energy and in kinetic energy was observed, which was correlated with an increase in uniaxial compression strength of coal. The share of dissipated energy is dominant in the total energy of strain. Share of recoverable energy in the total energy of strain is small, independent of the compression strength of coals and is at most a few per cent high. In coals of low strength and dominant share of dissipated energy, share of recoverable energy is the biggest among the tested coals. It was shown that following an increase in compression strength the share of recoverable energy decreases, while the share of dissipated energy in the total energy increases. Further studies of specific energy of longitudinal strain of rocks in the full-range strain will be the next step inperfecting methodology of research into natural rock burst susceptibility of Carboniferous rock mass and changes in the

Research of Heating Rates Influence on Layer Coal Gasification of Krasnogorsky And Borodinsky Coal Deposit

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Jankovskiy Stanislav

2015-01-01

Full Text Available Experimental research of heating rate influence on coal samples gasification process of Krasnogorsky and Borodinsky coal deposit ranks A and 2B was done to define optimal heating mode in high intensification of dispersal of inflammable gases conditions. Abundance ratio of carbon monoxide and nitrogen monoxide, water vapor, carbon dioxide at four values of heating rate within the range of 5 to 30 K/min. with further definition of optimal heating rate of coals was stated.

Economic aspects of coal deposits exploration of the Ulug-Khem basin (Tuva

Directory of Open Access Journals (Sweden)

Lebedev V.I.

2017-06-01

Full Text Available in accordance with the article, 11 deposits coal on the territory of Tuva are accounted by State Reserves Register of the Russian Federation, the total profitable reserves are estimated at 1,12 billion tons whereof 936.6 thousand tons are dealt with as coking coals. The vast majority of explored deposits of coals of the republic are concentrated in the Ulugh-Khem basin, the total projected resources of which exceed 20 bill.t. It is substantiated that coking coal of the Ulugh-Khem basin is the most competitive resource of Tyva Republic. Low ash content, excellent caking index, low sulfur and phosphorus in coking coal of ranks GG and GZh indicate their high quality, according to these characteristics GG, GZh coal ranks take precedence over Kuznetsk and Pechora coals. About 70 bill.t of coking coal are annually mined in Russia, but there is a deficit on certain coal ranks. It is primarily related to internal prices increase for coking coal in Russia. According to forecasts of researchers coal deficit will rise up to 15–17 bill.t in the country.

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.

Mercury distribution in coals influenced by magmatic intrusions, and surface waters from the Huaibei Coal Mining District, Anhui, China

International Nuclear Information System (INIS)

Yan, Zhicao; Liu, Guijian; Sun, Ruoyu; Wu, Dun; Wu, Bin; Zhou, Chuncai

2013-01-01

Highlights: • Hg concentrations in coal and surface water samples were determined. • Hg is enriched in the Huaibei coals. • Magmatic activities imparted influences on Hg content and distribution. • Hg contents in surface waters are relative low at the present status. - Abstract: The Hg concentrations in 108 samples, comprising 81 coal samples, 1 igneous rock, 2 parting rock samples and 24 water samples from the Huaibei Coal Mining District, China, were determined by cold-vapor atomic fluorescence spectrometry. The abundance and distribution of Hg in different coal mines and coal seams were studied. The weighted average Hg concentration for all coal samples in the Huaibei Coalfield is 0.42 mg/kg, which is about twice that of average Chinese coals. From southwestern to northeastern coalfield, Hg concentration shows a decreasing trend, which is presumably related to magmatic activity and fault structures. The relatively high Hg levels are observed in coal seams Nos. 6, 7 and 10 in the southwestern coal mines. Correlation analysis indicates that Hg in the southwestern and southernmost coals with high Hg concentrations is associated with pyrite. The Hg concentrations in surface waters in the Huaibei Coal Mining District range from 10 to 60 ng/L, and display a decreasing trend with distance from a coal waste pile but are lower than the regulated levels for Hg in drinking water

Microbially-Enhanced Coal Bed Methane: Strategies for Increased Biogenic Production

Science.gov (United States)

Davis, K.; Barhart, E. P.; Schweitzer, H. D.; Cunningham, A. B.; Gerlach, R.; Hiebert, R.; Fields, M. W.

2014-12-01

Coal is the largest fossil fuel resource in the United States. Most of this coal is deep in the subsurface making it costly and potentially dangerous to extract. However, in many of these deep coal seams, methane, the main component of natural gas, has been discovered and successfully harvested. Coal bed methane (CBM) currently accounts for approximately 7.5% of the natural gas produced in the U.S. Combustion of natural gas produces substantially less CO2 and toxic emissions (e.g. heavy metals) than combustion of coal or oil thereby making it a cleaner energy source. In the large coal seams of the Powder River Basin (PRB) in southeast Montana and northeast Wyoming, CBM is produced almost entirely by biogenic processes. The in situ conversion of coal to CBM by the native microbial community is of particular interest for present and future natural gas sources as it provides the potential to harvest energy from coal seams with lesser environmental impacts than mining and burning coal. Research at Montana State University has shown the potential for enhancing the subsurface microbial processes that produce CBM. Long-term batch enrichments have investigated the methane enhancement potential of yeast extract as well as algal and cyanobacterial biomass additions with increased methane production observed with all three additions when compared to no addition. Future work includes quantification of CBM enhancement and normalization of additions. This presentation addresses the options thus far investigated for increasing CBM production and the next steps for developing the enhanced in situ conversion of coal to CBM.

Characterization of a coal tailing deposit for zero waste mine in the Brazilian coal field of Santa Catarina

International Nuclear Information System (INIS)

Amaral Filho, J.R.; Schneider, I.A.H.; Tubino, R.M.C.; Brum de, I.A.S.; Miltzarek, G.; Sampaio, C.H.

2010-01-01

Coal tailings deposits in Brazil are occupying large areas of land while also generating acid mine drainage (AMD) that includes heavy metals. This paper described an analytical study of a typical coal tailings deposit. The study objective was to separate low density, intermediate density, and high density fractions for future reuse. Particle size analysis, disymmetric studies, X-ray diffraction, and tests conducted to determine ash, total sulphur, and acid bases were conducted in order to characterize the coal tailings samples. Results of the study demonstrated a size distribution of 67 percent coarse, 14 percent fine, and 19 percent ultra-fine particles. The gravimetric concentration method was used to recover 34.2 percent of the total deposit for future energy use. Approximately 9.2 percent of the remaining deposit was a pyrite concentrate. The acid generating potential of the remaining materials was reduced by approximately 60 percent. 9 refs., 1 tab., 2 figs.

Coal Mine Accidents in Bangladesh: Its Causes and Remedial Measures

Directory of Open Access Journals (Sweden)

MD. MINHAJ UDDIN MONIR

2012-12-01

Full Text Available Barapukuria coal mine (BCM is located at Dinajpur district, NW Bangladesh. Total area is about 6.68 km2 and coal was encountered at a depth ranging between 118 and 509 m. Six major coal seams (seam I to seam VI were identified at BCM, of which, thickest one is the seam-VI (~36 m. The estimated coal reserves is about 390 million tons and of this, nearly 64 million tons of coal is extractable. The annual production of coal is about 1 million ton. In this study several parameters were used to explore minimization of accidents and improvement of coal production in BCM. Considering the geological, hydrological and other technical parameters, longwall mining method is applied for extraction of coal. Longwall retreating mining method is also applied for extraction of coal from single face with the operational area protected by self-advancing hydraulic powered roof support (HPRS system. These supports are moved forward causing the roof behind them to form an extensive abandoned area named goaf, which may lead to collapse with air blast. Coal in BCM is extracted from seam VI, using a multislice Longwall top coal caving method. Average ventilated air composition is ~20.94% oxygen, ~79.00% nitrogen, ~0.04% carbon monoxide, and minor water steam with huge dust. Production of coal was completed from 12 Longwall faces of 1st slice from seam VI. During production period several accidents and troubles within BCM have occurred. Poisonous gases such as carbon monoxide were detected during/after development of 1110 Longwall face, which increases up to 6000 ppm, therefore, sealed-off the face with mining equipments. During the development of belt gate roadway of 1101 Longwall face, maximum temperature and humidity increases up to 37 oC and 100%, respectively. Miners of BCM experienced some difficulties to work in that adverse environment. Air return roadway temperature was always 40 to 41oC in 1101 Longwall face during production period, faces temperature 46o

Coal resources availability in Botswana

International Nuclear Information System (INIS)

Modisi, M.P.

1990-01-01

This paper reports that Southern Africa, and Botswana in particular, is well-endowed with relatively large reserves of coal. The existence of coal in Botswana has been known since the end of the last century. Exploration activities by the Geological Survey and the private sector led to the discovery of major deposits and by the late 1960s reserves capable of supporting a mine at Morupule for the domestic market has been confirmed. The oil crises of 1973-74 and 1978-79 stimulated increased interest in coal exploration the world over and Botswana attracted several private sector companies looking for coal that could be traded on the international market. As a result vast resources and reserves of low to medium quality bituminous coal, suitable for the export market, were proved. Resources amounting to 21,680 million tonnes of in situ coal had been revealed by 1987. Reserves of possible economic exploitation are estimated at 10,180 million tonnes in two coal field areas, namely the Morupule Coal Field and the Mmamabula Coal Field. Since the collapse of oil prices and consequently coal prices in the mid-1980s, enthusiasm for coal exploration has plummeted and relatively little prospecting has taken place. The coal occurs within the Upper Carboniferous to Jurassic Karoo Supergroup which underlies some 60 percent of the country's land surface. The western part of the country is mantled by the Kalahari beds, a top layer of unconsolidated sands masking bedrock geology. Although coal seams have been intersected in boreholes in this western area, most exploration activity has taken place in the eastern part of the country where the Morupule and Mmamabula coal fields are located. It is in the east that most of the population is concentrated and infrastructure has been developed

A Coal Burst Mitigation Strategy for Tailgate during Deep Mining of Inclined Longwall Top Coal Caving Panels at Huafeng Coal Mine

Directory of Open Access Journals (Sweden)

Guorui Feng

2018-01-01

Full Text Available A coal burst mitigation strategy for tailgate in mining of deep inclined longwall panels with top coal caving at Huafeng Coal Mine is presented in this paper. Field data showed that coal bursts, rib sloughing or slabbing, large convergence, and so forth frequently occurred within the tailgate entries during development and panel retreating employing standard longwall top coal caving (LTCC layout which resulted in fatal injuries and tremendous profit loss. The contributing factors leading to coal bursts were analyzed. Laboratory tests, in situ measurement, and field observation demonstrate that the intrinsic bursting proneness of the coal seam and immediate roof stratum, deep cover, overlying ultrathick (500–800 m conglomerate strata, faults, and, most importantly, improper panel layout led to coal bursts. By employing a new strategy, that is, longwall mining with split-level gateroads (LMSG, gateroads on either end of a LMSG panel are located at different levels within a coal seam, adjacent LMSG panels overlap end to end, and the tailgate of the adjacent new LMSG panel can be located below the headgate entry of the previous LMSG panel or may be offset horizontally with respect to it. Numerical modeling was carried out to investigate the stress distribution and yield zone development within surrounding rock mass which was validated by field investigation. The results indicate that standard LTCC system gave rise to high ground pressure around tailgate entries next to the gob, while LMSG tailgate entry below the gob edge was in a destressed environment. Therefore, coal bursts are significantly mitigated. Field practice of LMSG at Huafeng Coal Mine demonstrates how the new strategy effectively dealt with coal burst problems in mining of deep inclined longwall panels with a reduced incidence of ground control problems. The new strategy can potentially be applied in similar settings.

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.

Origin of discontinuities in coal-bearing strata at Roaring Creek (Basal Pennsylvanian of Indiana)

Energy Technology Data Exchange (ETDEWEB)

Nelson, W J; Eggert, D L; Dimichele, W A; Stecyk, A C

1985-05-01

Basal Pennsylvanian coal-bearing strata exposed along Roaring Creek, west-central Indiana, exhibit extreme lateral discontinuity. Coal seams abruptly change in thickness and elevation; they split, grade into shale, are cut out by channels and disrupted by soft-sediment deformational structures. Initial sediments were laid down by a network of southwest- flowing streams that traversed a deeply channelized upland surface of Mississippian carbonate rocks. Channels aggraded rapidly as uplands were worn down, so the region changed through time from uplands to upper deltaic plain. Local environments included channels, localized point bars, small natural levees and crevasse splays, overbank deposits, and swamps. Differential compaction and subsidence, slumping stream banks, and possibly collapsing sinkholes influenced sedimentation. As a consequence, coals are too discontinuous for economical mining, although they are locally thick and high in quality. 16 references.

Exploring the determinants of health and wellbeing in communities living in proximity to coal seam gas developments in regional Queensland.

Science.gov (United States)

Mactaggart, Fiona; McDermott, Liane; Tynan, Anna; Gericke, Christian A

2017-08-03

There is some concern that coal seam gas mining may affect health and wellbeing through changes in social determinants such as living and working conditions, local economy and the environment. The onward impact of these conditions on health and wellbeing is often not monitored to the same degree as direct environmental health impacts in the mining context, but merits attention. This study reports on the findings from a recurrent theme that emerged from analysis of the qualitative component of a comprehensive Health Needs Assessment (HNA) conducted in regional Queensland: that health and wellbeing of communities was reportedly affected by nearby coal seam gas (CSG) development beyond direct environmental impacts. Qualitative analysis was initially completed using the Framework Method to explore key themes from 11 focus group discussions, 19 in-depth interviews, and 45 key informant interviews with health and wellbeing service providers and community members. A key theme emerged from the analysis that forms the basis of this paper. This study is part of a larger comprehensive HNA involving qualitative and quantitative data collection to explore the health and wellbeing needs of three communities living in proximity to CSG development in regional Queensland, Australia. Communities faced social, economic and environmental impacts from the rapid growth of CSG development, which were perceived to have direct and indirect effects on individual lifestyle factors such as alcohol and drug abuse, family relationships, social capital and mental health; and community-level factors including social connectedness, civic engagement and trust. Outer regional communities discussed the effects of mining activity on the fabric of their town and community, whereas the inner regional community that had a longer history of industrial activity discussed the impacts on families and individual health and wellbeing. The findings from this study may inform future health service planning in

Study on Fluid-solid Coupling Mathematical Models and Numerical Simulation of Coal Containing Gas

Science.gov (United States)

Xu, Gang; Hao, Meng; Jin, Hongwei

2018-02-01

Based on coal seam gas migration theory under multi-physics field coupling effect, fluid-solid coupling model of coal seam gas was build using elastic mechanics, fluid mechanics in porous medium and effective stress principle. Gas seepage behavior under different original gas pressure was simulated. Results indicated that residual gas pressure, gas pressure gradient and gas low were bigger when original gas pressure was higher. Coal permeability distribution decreased exponentially when original gas pressure was lower than critical pressure. Coal permeability decreased rapidly first and then increased slowly when original pressure was higher than critical pressure.

Mining a coal seam with caving in a protective pillar of a mine shaft. [Poland

Energy Technology Data Exchange (ETDEWEB)

Szymura, G; Dilling, R; Kowalski, A

1984-01-01

Mining the 620 seam is evaluated (from 1.5 to 1.7 m thick at a depth of 468 m in the protective pillar of the upcast mine shaft used for ventilation, manriding and transport of materials in the Pstrowski mine in Upper Silesia). The shaft is 496 m deep, has a diameter of 3.5 m and its liners are made of bricks. Ground subsidence caused by underground mining influenced: the head frame above the shaft, residential buildings, a church, railway tracks and a river bed. A system of shortwall mining with caving was used. Deformation of shaft liners was reduced by advanced cutting of a coal block 30x30 m around the shaft. A system of timber cribbings and yielding elements was used. Design of support systems used around the shaft is shown in 3 schemes. Shaft deformation was within permissible limits. The maximum ground subsidence (0.95 m) occurred in the river area. Ground subsidence in the area of the church ranged from 0.75 to 0.81 m and in the head frame area 0.84 m. Accuracy of ground subsidence and shaft deformation forecasting was high. 4 references.

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.

Coal characteristics from 'Priskupshtina' deposit and technological parameters for briquetting (Macedonia)

International Nuclear Information System (INIS)

Damjanovski, Dragan

1998-01-01

The use of small class coal as well as the lack of formed fuel needed for the industry and for the consumer goods has been a long lasting problem, and a challenge for the researchers of the Republic of Macedonia. For that purpose, all-inclusive analysis of the quality of the coals in Macedonia, their reserves and technical characteristics, as well as analysis of the petrographic structure were made. Classification of the deposits and the research for the possibility of making briquettes was done, too. Laboratory investigations in the coal deposit 'Priskupshtina' were carried out. The analysis of the coal briquetting show that the expected results in coordination with the required standards were not obtained. Spatially the results from the coal calorific value, its hardness and atmospheric resistance. Standard methods were used for the researches without connective means and the achieved results were mutually correlated. Technical-economic verification is necessary in the further process. (Author)

Prior infusion of water into the seam and its effects in the behavior of methane

Energy Technology Data Exchange (ETDEWEB)

Degueldre, G

1975-01-01

Infusion of the seam is carried out in advance of the face to control dust but it has been found that it also reduces the rate of desorption of methane. Since the methane is retained in the coal, less is present in the mine air. Guidelines for the infusion process are given, and experience in using it is described. The effect on the water content of the coal and on the dust is described.

Competitiveness and potentials of UCG-CCS on the European energy market

Science.gov (United States)

Kempka, T.; Nakaten, N.; Schlüter, R.; Fernandez-Steeger, T.; Azzam, R.

2009-04-01

The world-wide coal reserves can satisfy the world's primary energy demand for several hundred years. However, deep coal deposits with seams of low thickness and structural complexity do currently not allow an economic exploitation of many deposits. Here, underground coal gasification (UCG) can offer an economical approach for coal extraction. The intended overall process relies on coal deposit exploitation using directed drillings located at the coal seam base and the subsequent in situ coal conversion into a synthesis gas. The resulting synthesis gas is used for electricity generation in a combined cycle plant at the surface. A reduction of the CO2 emissions resulting from the combined process is realized by subsequent CO2 capture and its injection into the previously gasified coal seams. The scope of the present study was the investigation of UCG-CCS competitiveness on the European energy market and the determination of the impacting factors. For that purpose, a modular model for calculation of UCG-CCS electricity generation costs was implemented and adapted to the most relevant process parameters. Furthermore, the range of energy supply coverage was estimated based on different German energy generation scenarios.

Indication to distinguish the burst region of coal gas from seismic data

Energy Technology Data Exchange (ETDEWEB)

Jian-yuan Cheng; Hong-wei Tang; Lin Xu; Yan-fang Li [China Coal Research Institute, Xi' an (China). Xi' an Research Institute

2009-09-15

The velocity of an over-burst coal seam is about 1/3 compared to a normal coal seam based on laboratory test results. This can be considered as a basis to confirm the area of coal and gas burst by seismic exploration technique. Similarly, the simulation result of the theoretical seismic model shows that there is obvious distinction between over-burst coal and normal coal based on the coal reflection's travel-time, energy and frequency. The results from the actual seismic data acquired in the coal and gas over-burst cases is consistent with that of the laboratory and seismic modeling; that is, in the coal and gas burst region, seismic reflection travel time is delayed, seismic amplitude is weakened and seismic frequency is reduced. Therefore, it can be concluded that seismic exploration technique is promising for use in distinguishing coal and gas over-burst regions based on the variation of seismic reflection travel time, amplitude and frequency. 7 refs., 6 figs.

Preparation and combustion of coal-water fuel from the Sin Pun coal deposit, southern Thailand

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-05-01

In response to an inquiry by the Department of Mineral Resources in Thailand, the Energy & Environmental Research Center (EERC) prepared a program to assess the responsiveness of Sin Pun lignite to the temperature and pressure conditions of hot-water drying. The results indicate that drying made several improvements in the coal, notably increases in heating value and carbon content and reductions in equilibrium moisture and oxygen content. The equilibrium moisture content decreased from 27 wt% for the raw coal to about 15 wt% for the hot-water-dried (HWD) coals. The energy density for a pumpable coal-water fuel (CWF) indicates an increase from 4500 to 6100 Btu/lb by hot-water drying. Approximately 650 lb of HWD Sin Pun CWF were fired in the EERC`s combustion test facility. The fuel burned extremely well, with no feed problems noted during the course of the test. Fouling and slagging deposits each indicated a very low rate of ash deposition, with only a dusty layer formed on the cooled metal surfaces. The combustor was operated at between 20% and 25% excess air, resulting in a flue gas SO{sub 2} concentration averaging approximately 6500 parts per million.

Report on the FY 1989 potential survey of overseas coal development. Coal fields in Indonesia; 1989 nendo kaigaitan kaihatsu kanosei chosa hokokusho. Indonesia kyowakoku kaku tanden

Energy Technology Data Exchange (ETDEWEB)

NONE

1989-12-01

This survey is aimed at acquiring the basic data required for judging a possibility of development/import of steam coal in Indonesia (west of Java, north of Sumatra and west of Sumatra). Areas for survey are Meulaboh coal field in north Sumatra, Ombilin III area in West Sumatra, and Bayah coal field in West Java. The survey includes the field survey to grasp the situation of coal seam existence, coal quality, coal amount, etc. and activities for collecting the related data and information from the organizations concerned. The Meulaboh coal field has a technical possibility of open pit mining of medium scale. However, the heating value is extremely low, around 4,300 kcal/kg. Judging from this coal quality, there is no possibility of exporting it. It can be said that Ombilin coal is the world's top class steam coal. Accordingly, the demand can be expected both in export use and domestic use. As to Bayah coal, Bemmelen (1949) concluded that the coal was extremely excellent in quality, but had great disadvantages such as thin coal seam, discontinuity, and complicated geological structure. To date, the conclusion has been unchanged. (NEDO)

Detection and delineation of coal mine fire in Jharia coal field (JCF ...

Indian Academy of Sciences (India)

71

Africa, Indonesia, Poland (Zhang et al. 2005; Kuenzer et al. .... is about 8 Km in west direction from Dhanbad Rrailway station. The location of the ...... International conference on Spontaneous coal seam fires: Mitigating a global. 543 disaster at ...

Stress analysis of longwall top coal caving

Energy Technology Data Exchange (ETDEWEB)

Alehossein, H.; Poulsen, B.A. [CSIRO Exploration & Mining, Brisbane, Qld. (Australia)

2010-01-15

Longwall top coal caving (LTCC) is a relatively new method of mining thick coal seams that is currently achieving high productivity and efficiency. The technique is similar to traditional longwall mining in that a cutting head slices coal from the lower section of the coal seam onto a conveyor belt installed in front of the hydraulic support near the cutting face. In modern LTCC an additional rear conveyor belt is located behind the support, to which the flow of the caved coal from the upper part of the seam can be controlled by a moveable flipper attached to the canopy of the support. The mining method relies on the fracturing of the top coal by the front abutment pressure to achieve satisfactory caving into the rear conveyor. This paper develops a yield and caveability criterion based on in situ conditions in the top coal in advance of the mining face (yield) and behind the supports (caveability). Yielding and caving effects are combined into one single number called caving number (CN), which is the multiplication result of caving factor (CF) and yield factor (YF). Analytical derivations are based on in situ stress conditions, Mohr-Coulomb and/or Hoek-Brown rock failure criteria and an on-associated elastoplastic strain softening material behaviour. The yield and caveability criteria are in agreement with results from both numerical studies and mine data. The caving number is normalised to mining conditions of a reference Chinese mine (LMX mine) and is used to assess LTCC performance at fourteen other Chinese working longwalls that have had varying success with the LTCC technology. As a predictive model, results of this analytical/numerical study are useful to assess the potential success of caving in new LTCC operations and in different mining conditions.

Theoretical basis for transfer of laboratory test results of grain size distribution of coal to real object

Energy Technology Data Exchange (ETDEWEB)

Sikora, W; Chodura, J [Politechnika Sladska, Gliwice (Poland). Instytut Mechanizacji Gornictwa

1989-01-01

Evaluates a method for forecasting size distribution of black coal mined by shearer loaders in one coal seam. Laboratory tests for determining coal comminution during cutting and haulage along the face are analyzed. Methods for forecasting grain size distribution of coal under operational conditions using formulae developed on the basis of laboratory tests are discussed. Recommendations for design of a test stand and test conditions are discussed. A laboratory stand should accurately model operational conditions of coal cutting, especially dimensions of the individual elements of the shearer loader, geometry of the cutting drum and cutting tools, and strength characteristics of the coal seam. 9 refs.

Deposit Formation in a 150 MWe Utility PF-Boiler during Co-combustion of Coal and Straw

DEFF Research Database (Denmark)

Andersen, Karin Hedebo; Frandsen, Flemming; Hansen, P. F. B.

2000-01-01

A conventional pc-fired boiler at the Danish energy company I/S Midtkraft has been converted to coal-straw co-combustion, and a 2 year demonstration program was initiated in January 1996, addressing several aspects of coal-straw co-combustion. Deposition trials were performed as part of the demon......A conventional pc-fired boiler at the Danish energy company I/S Midtkraft has been converted to coal-straw co-combustion, and a 2 year demonstration program was initiated in January 1996, addressing several aspects of coal-straw co-combustion. Deposition trials were performed as part...... problematic deposits. Go-firing straw also caused a change in the structure of the upstream deposits. During coal combustion an ordered, "finger" structure of the larger particles with small particles between was observed, whereas during co-combustion a more random deposition of the larger particles among...... arise when burning other coals, particularly coals with a high S or alkali metal content or a low content of ash. The behavior of K, Ca, S, and Cl was evaluated by use of thermodynamic calculations. The thermodynamically stable species agree with the observed behavior in the experiments, i.e. formation...

Characterisation of South African coals using instrumental neutron activation analysis

International Nuclear Information System (INIS)

Hart, R.J.

1985-01-01

This report includes the establishment of the major minor and trace element compositions of South African coals with the aim of characterising the different coal seams within a basin, defining regions of similar compositions and obtaining an overall view of the geochemistry of coals in this country. The results of 40 coal samples analysed by neutron activation analysis

Investigation of trace elements in coal

International Nuclear Information System (INIS)

Gluskoter, H.J.; Cahil, R.A.; Miller, W.G.; Ruch, R.R.; Shimp, N.F.

1976-01-01

A variety of coal samples is currently being extensively analyzed for constituents, including many trace elements, at the Illinois State Geological Survey. The samples include whole coals, washed coals, and bench samples. Among the many determinations made on each sample are analyses for approximately 60 elements, almost twice the number of elements previously determined. The increase is in part the result of the addition of instrumental neutron activation analysis (INAA) equipment to the laboratory. Twenty-five samples of Herrin (No. 6) Coal that had been analyzed previously were subjected to INAA analysis and were found to include Ba, Ce, Cs, Dy, Eu, Au, Hf, I, In, La, Lu, Rb, Sm, Sc, Ag, Sr, Ta, Tb, Th, W, U, and Yb, none of which were reported by previous techniques. These elements generally are present in very small amounts and, with the exception of barium, exhibit no wide range in concentration. The rare earth elements are among those having the narrowest ranges. Wide variations in element content have been observed in bench sets of coals (samples of vertical segments of the coal seam). Many elements, notably germanium, are concentrated at the top and/or bottom of the seam, the high concentrations of Ge being found there in all four bench sets analyzed to date

Petrography and microanalysis of Pennsylvanian coal-ball concretions (Herrin Coal, Illinois Basin, USA): Bearing on fossil plant preservation and coal-ball origins

Science.gov (United States)

Siewers, Fredrick D.; Phillips, Tom L.

2015-11-01

Petrographic analyses of 25 coal balls from well-studied paleobotanical profiles in the Middle Pennsylvanian Herrin Coal (Westphalian D, Illinois Basin) and five select coal balls from university collections, indicate that Herrin Coal-ball peats were permineralized by fibrous and non-fibrous carbonates. Fibrous carbonates occur in fan-like to spherulitic arrays in many intracellular (within tissue) pores, and are best developed in relatively open extracellular (between plant) pore spaces. Acid etched fibrous carbonates appear white under reflected light and possess a microcrystalline texture attributable to abundant microdolomite. Scanning electron microscopy, X-ray diffraction, and electron microprobe analysis demonstrate that individual fibers have a distinct trigonal prism morphology and are notable for their magnesium content (≈ 9-15 mol% MgCO3). Non-fibrous carbonates fill intercrystalline spaces among fibers and pores within the peat as primary precipitates and neomorphic replacements. In the immediate vicinity of plant cell walls, non-fibrous carbonates cut across fibrous carbonates as a secondary, neomorphic phase attributed to coalification of plant cell walls. Dolomite occurs as diagenetic microdolomite associated with the fibrous carbonate phase, as sparite replacements, and as void-filling cement. Maximum dolomite (50-59 wt.%) is in the top-of-seam coal-ball zone at the Sahara Mine, which is overlain by the marine Anna Shale. Coal-ball formation in the Herrin Coal began with the precipitation of fibrous high magnesium calcite. The trigonal prism morphology of the carbonate fibers suggests rapid precipitation from super-saturated, meteoric pore waters. Carbonate precipitation from marine waters is discounted on the basis of stratigraphic, paleobotanical, and stable isotopic evidence. Most non-fibrous carbonate is attributable to later diagenetic events, including void-fill replacements, recrystallization, and post-depositional fracture fills. Evidence

In situ analysis of coal from single electrode resistance, self-potential and gamma-ray logs

International Nuclear Information System (INIS)

Kayal, J.R.

1981-01-01

Single electrode resistance, self-potential and gamma-ray logging have been carried out in North Karanpura, West Bokaro and Jharia coalfields of Gondwana basin in Eastern India. Correlation of these geophysical logs is found to be very useful in locating the coal beds, determining their accurate depths and thickness and approximate quality. Coal seams have been detected as very high resistive formations compared to sandstone/shale which are interbedded in the coal basin. High or low self-potential values are obtained against the coal beds depending on the borehole fluid conditions. Burnt coals (Jhama) are characterised as highly conductive beds. Gamma ray logs have been effectively used alongwith electrical logs for correlation and identification of coal seams. Further analysis of gamma-ray log data determines a linear relationship with ash content of coal. (author)

Seismic characterization of CO{sub 2} in coals

Energy Technology Data Exchange (ETDEWEB)

McCrank, J.; Lawton, D.C. [Calgary Univ., AB (Canada). Dept. of Geoscience, Consortium for Research in Elastic Wave Exploration Seismology

2008-07-01

The Mynheer coal seam was targeted for an enhanced coalbed methane (CBM) experiment. During initial testing of the reservoir permeability, 180 tonnes of carbon dioxide (CO{sub 2}) was injected into the seam. The objective of the study was to characterize the coal zones and to determine if the small volume of CO{sub 2} in the thinly bedded and seismically tuned reservoir can be detected in the 3D surface seismic data. The multi-well pilot project took place in the Pembina Field of west-central Alberta. The Ardley coals were tested for CO{sub 2} injection, enhanced CBM production, and CO{sub 2} sequestration. The seismic survey captured the condition of the reservoir after formation permeability tests. It was concluded that the anomalies seen in the seismic data can be attributed to changes in the physical properties of the coal due to CO{sub 2} adsorption. 2 refs., 5 figs.

Ore controlling oxidized zonation epigenetic uranium-coal deposits and regularities in lignite transformations

International Nuclear Information System (INIS)

Uspenskij, V.A.; Kulakova, Ya.M.

1982-01-01

Complex of analytical methods was used to study epigenetic transformations in uranium-coal ore manifestation. To clarify the principle scheme of oxidized zonation in coals the materials, related to three similar objects were used. When comparing obtained epigenetic column with columns of similar ore objects the principle scheme of oxidized epigenetic zonation for ancient infiltration uranium-coal deposits was specified; general regularities of eignite transformations and characteristics of profile distribution of uranium and accessory metal zonations were revealed. Infiltration processes, proceeded in coal measureses, formed the steady epigenetic oxidized zonation: O - zone of barren unoxidized coals, 1 - zone of ore-bearing unoxidized coals, 2 - zone of weakly ore-bearing oxidized coals, 3 - zone of oxidized terrigenous rocks with zonules of development of yellow and red iron hydroxides. Capacities of some zones and zonules reflect the intensity and duration of ore-forming processes. Distribution of U and accessory elements obeys completely epigenetic zonation. It is assumed, that ancient infiltration uranium-coal deposits formed due to weakly uranium-bearing oxygen-containing waters

Low-rank coal study : national needs for resource development. Volume 2. Resource characterization

Energy Technology Data Exchange (ETDEWEB)

1980-11-01

Comprehensive data are presented on the quantity, quality, and distribution of low-rank coal (subbituminous and lignite) deposits in the United States. The major lignite-bearing areas are the Fort Union Region and the Gulf Lignite Region, with the predominant strippable reserves being in the states of North Dakota, Montana, and Texas. The largest subbituminous coal deposits are in the Powder River Region of Montana and Wyoming, The San Juan Basin of New Mexico, and in Northern Alaska. For each of the low-rank coal-bearing regions, descriptions are provided of the geology; strippable reserves; active and planned mines; classification of identified resources by depth, seam thickness, sulfur content, and ash content; overburden characteristics; aquifers; and coal properties and characteristics. Low-rank coals are distinguished from bituminous coals by unique chemical and physical properties that affect their behavior in extraction, utilization, or conversion processes. The most characteristic properties of the organic fraction of low-rank coals are the high inherent moisture and oxygen contents, and the correspondingly low heating value. Mineral matter (ash) contents and compositions of all coals are highly variable; however, low-rank coals tend to have a higher proportion of the alkali components CaO, MgO, and Na/sub 2/O. About 90% of the reserve base of US low-rank coal has less than one percent sulfur. Water resources in the major low-rank coal-bearing regions tend to have highly seasonal availabilities. Some areas appear to have ample water resources to support major new coal projects; in other areas such as Texas, water supplies may be constraining factor on development.

Hydrochemical processes in a shallow coal seam gas aquifer and its overlying stream–alluvial system: implications for recharge and inter-aquifer connectivity

International Nuclear Information System (INIS)

Duvert, Clément; Raiber, Matthias; Owen, Daniel D.R.; Cendón, Dioni I.; Batiot-Guilhe, Christelle; Cox, Malcolm E.

2015-01-01

Highlights: • Major ions and isotopes used to study inter-aquifer mixing in a shallow CSG setting. • Considerable heterogeneity in the water composition of the coal-bearing aquifer. • Rapid recharge of the coal-bearing aquifer through highly fractured igneous rocks. • Potential mixing between the coal-bearing aquifer and downstream alluvial aquifer. • Need to consider the seasonal influences on inter-aquifer mixing in CSG settings. - Abstract: In areas of potential coal seam gas (CSG) development, understanding interactions between coal-bearing strata and adjacent aquifers and streams is of highest importance, particularly where CSG formations occur at shallow depth. This study tests a combination of hydrochemical and isotopic tracers to investigate the transient nature of hydrochemical processes, inter-aquifer mixing and recharge in a catchment where the coal-bearing aquifer is in direct contact with the alluvial aquifer and surface drainage network. A strong connection was observed between the main stream and underlying alluvium, marked by a similar evolution from fresh Ca–Mg–HCO 3 waters in the headwaters towards brackish Ca–Na–Cl composition near the outlet of the catchment, driven by evaporation and transpiration. In the coal-bearing aquifer, by contrast, considerable site-to-site variations were observed, although waters generally had a Na–HCO 3 –Cl facies and high residual alkalinity values. Increased salinity was controlled by several coexisting processes, including transpiration by plants, mineral weathering and possibly degradation of coal organic matter. Longer residence times and relatively enriched carbon isotopic signatures of the downstream alluvial waters were suggestive of potential interactions with the shallow coal-bearing aquifer. The examination of temporal variations in deuterium excess enabled detection of rapid recharge of the coal-bearing aquifer through highly fractured igneous rocks, particularly at the catchment

A Case Study of Damage Energy Analysis and an Early Warning by Microseismic Monitoring for Large Area Roof Caving in Shallow Depth Seams

Directory of Open Access Journals (Sweden)

Like Wei

2015-01-01

Full Text Available Shallow depth coal seams are widely spread in Shendong mining area, which is located in the Northwestern region of China. When working face is advanced out of concentrated coal pillar in upper room and pillar goaf, strong strata behaviors often cause support crushing accidents, and potentially induce large area residual pillars instability and even wind blast disaster. In order to predict the precise time when the accident happens, guaranteeing life-safety of miner, microseismic monitoring system was for the first time applied in shallow coal seam. Based on damage mechanics correlation theory, the damage energy model is established to describe relationship between damage level and cumulative energy of microseismic events. According to microseismic monitoring data of two support crushing accidents, the damage energy model is verified and an effective early warning method of these accidents is proposed. The field application showed that the early warning method had avoided miners suffering from all support crushing accidents in Shigetai coal mine.

Test and evaluate the tri-gas low-Btu coal-gasification process. Final report, October 21, 1977-October 31, 1980

Energy Technology Data Exchange (ETDEWEB)

Zabetakis, M.G.

1980-12-01

This report describes the continuation of work done to develop the BCR TRI-GAS multiple fluidized-bed gasification process. The objective is the gasification of all ranks of coals with the only product being a clean, low-Btu fuel gas. Design and construction of a 100 lb/h process and equipment development unit (PEDU) was completed on the previous contract. The process consists of three fluid-bed reactors in series, each having a specific function: Stage 1 - pretreatment; Stage 2- - gasification; Stage 3 - maximization of carbon utilization. Under the present contract, 59 PEDU tests have been conducted. A number of these were single-stage tests, mostly in Stage 1; however, integrated PEDU tests were conducted with a western coal (Rosebud) and two eastern coals (Illinois No. 6 and Pittsburgh seam). Both Rosebud and Pittsburgh seam coals were gasified with the PEDU operating in the design mode. Operation with Illinois No. 6 seam coal was also very promising; however, time limitations precluded further testing with this coal. One of the crucial tasks was to operate the Stage 1 reactor to pretreat and devolatilize caking coals. By adding a small amount of air to the fluidizing gas, the caking properties of the coal can be eliminated. However, it was also desirable to release a high percentage of the volatile matter from the coal in this vessel. To accomplish this, the reactor had to be operated above the agglomerating temperature of caking coals. By maintaining a low ratio of fresh to treated coal, this objective was achieved. Both Illinois No. 6 and Pittsburgh seam coals were treated at temperatures of 800 to 900 F without agglomerating in the vessel.

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

Study on the change law of soil in subsidence area of horizontal coal seam

Science.gov (United States)

Li, Pengfeng; Wang, Shugang; Liu, Wei

2017-11-01

In order to provide theoretical basis for land reclamation in subsidence area, the mining subsidence area is divided into three areas: zone I (stretching zone), zone II (compression zone) and zone III (neutral zone). On this basis, the change characteristics of the soil in the three areas of the horizontal coal seam mining subsidence area are studied. The results show that: due to stretching, soil of zone I cracks was developed, the soil continuity damage, poor integrity, serious leakage of soil Water Leakage fertilizer, the area shows the soil water holding capacity decreased, the decline of soil fertility, soil coarsening and barren trend. The soil mass in zone II is compressed and the soil structure is relatively complete, but the soil bulk density increases correspondingly, while the soil porosity decreases gradually and the permeability decreases. The main soil layer in the zone III is vertical deformation, and the soil integrity is better. But the influence of mined out area leads to the movement of water and nutrients to the lower part of the soil. This paper suggests that in the land reclamation process should adopt corresponding reclamation method based on the variation law of the three soil area of reclamation area of mining subsidence, for improving soil physicochemical properties, so as to achieve the purpose of effective reclamation.

Effect of microwave irradiation on petrophysical characterization of coals

International Nuclear Information System (INIS)

Hong, Yi-du; Lin, Bai-quan; Zhu, Chuan-jie; Li, He

2016-01-01

Highlights: • Microwave energy increase porosity, pore size and numbers of coals. • Growth rates of porosity decreased at first then increased with microwave energy. • NMR can be reliable to measure coal samples. • Microwave energy may have the potential for degassing of coal seams. - Abstract: The experimental work described in this paper aims to study the effect of microwave irradiation on petrophysical characterization of coals. Twenty coal samples were irradiated at 2.45 GHz with variable power (2, 4, 6 kW). The temperature, mass and specific heat capacity of coal samples were measured and calculated. The effect of microwave irradiation on the porosity of coal samples was evaluated by the gravimetric method and nuclear magnetic resonance (NMR) measurements. The porosity obviously increases after microwave heating. Interestingly, growth rate of the porosity decreases at first then increases with microwave energy. The turning point is approximately 100 kJ. The influence of microwave irradiation on pore size, throat size and pore numbers of coal samples were also evaluated by NMR measurements. It suggest that the pore size, throat size and pore numbers are obviously increase with microwave energy. In a word, it appears likely that microwave energy may have the potential for the degassing coal seams.

A depositional model for the Taylor coal bed, Martin and Johnson counties, eastern Kentucky

Science.gov (United States)

Andrews, W.M.; Hower, J.C.; Ferm, J.C.; Evans, S.D.; Sirek, N.S.; Warrell, M.; Eble, C.F.

1996-01-01

This study investigated the Taylor coal bed in Johnson and Martin counties, eastern Kentucky, using field and petrographic techniques to develop a depositional model of the coal bed. Petrography and chemistry of the coal bed were examined. Multiple benches of the Taylor coal bed were correlated over a 10 km distance. Three sites were studied in detail. The coal at the western and eastern sites were relatively thin and split by thick clastic partings. The coal at the central site was the thickest and unsplit. Two major clastic partings are included in the coal bed. Each represents a separate and distinct fluvial splay. The Taylor is interpreted to have developed on a coastal plain with periodic flooding from nearby, structurally-controlled fluvial systems. Doming is unlikely due to the petrographic and chemical trends, which are inconsistent with modern Indonesian models. The depositional history and structural and stratigraphic setting suggest contemporaneous structural influence on thickness and quality of the Taylor coal bed in this area.

FY 1999 report on the survey of the overseas geological structure, etc. Japan-Indonesia joint Tanjung Enim coal exploration project; 1999 nendo kaigai chishitsu kozo nado chosa hokokusho. Nippon Indonesia sekitan kyodo tansa Tanjung Enim project

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The paper summed up the FY 1999 results of the survey conducted based on the agreement on the Tanjung Enim IV coal exploration project which was concluded between NEDO and Indonesia's Ministry of Mining Energy. The survey was made for an area of approximately 40km{sup 2} which is a north block of the south Arahan region, Tanjung Enim, South Sumatra, Indonesia. To grasp the succession of strata/rock facies/geological structure and the state of existence of the coal seams to be drilled, surveys were conducted on ground surface and boreholes. A total of 10 holes was test-drilled, and all the boreholes were physically logged. As a result of the survey, each of A1, A2, B, C and E coal seams was confirmed as main seams. A1, A2 and B seams are low in ash and sulfur contents with heating values of approximately 4,800 kcal/kg, C seam is high in sulfur content, and E seam is high in heating value, 6,000 kcal/kg. As coal seams for open pit mining, existence of A, B and C seams is expected which lay in the shallow part from ground surface to sea level of 0m and in the range of depth of approximately 100m. The proved coal reserves of these coals were estimated at 189 million tons. (NEDO)

Java Persistence Dengan JBoss Seam

OpenAIRE

Utomo, Wiranto Herry; Istiyanto, Jazi Eko

2009-01-01

Seam is based on Java EE, so it satisfies its framework duties in two fundamental ways: 1) Seam  simplifies Java EE: Seam provides a number of  shortcuts and  simplifications  to  the standard  Java EE  framework, making  it  even  easier  to  effectively  use  Java EE web  and business components, 2) Seam extends Java EE: Seam integrates a number of new concepts and tools into the Java EE framework. These extensions b...

FY 2000 report on the survey of the overseas geological structure. Japan-China joint coal exploration - Yu Xian project; 2000 nendo kaigai chishitsu kozo nado chosa hokokusho. Nippon Chugoku sekitan kyodo tansa Yu Xian project

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

The geological survey was carried out which is needed for coal mine design in the Yu Xian coal mine area, Yu Xian coal field, Hebei province, China. The term of survey was 5 years from 1996 to 2000. Activities are mainly for seismic survey and boring survey. Japan was in charge of the seismic survey, and China in charge of the boring survey. Both attained the goal. The results of the activities were summed up in the following 7 items: 1) outline of the survey; 2) general investigation; 3) state of the exploration related materials/machinery; 4) field survey; 5) items of survey; 6) results of the survey; 7) conclusion. In 6), the geological analysis, coal quality survey and coal amount survey were conducted. In the geological analysis, analyzed were the succession of strata, geological structure, and the situation of existence of coal seams. In 7), the following were made clear: geological structure of the survey area, coal seam, coal quality, hydrological geology, other conditions of drilling technology, and coal amount. The coal amount was 328.34 million tons in a total of A/B/C class coals. The total coal amount of Nos. 1 and 5 coal seams was 259.79 million tons, which was 79.1% of the total coal amount in all area. The average thickness of Nos. 1 and 5 coal seams, which are the main minable coal seams, was 3.10m and 2.66m, respectively. (NEDO)

Mineralogic and element association of coals from the Gevra mine, Korba coal field, Madhya Pradesh, India

International Nuclear Information System (INIS)

Hart, B.R.; Powell, M.A.; Fyfe, W.S.; Sahu, K.C.; Tripathy, S.

1991-01-01

As a part of a project to study the content and distribution of trace elements in coals and coal by-products from coal mining areas of India, the mineral and elemental composition of the whole coal and concentration of the selective elements in the whole coal mined from the Gevra mine of the Korba coal field in Madhya Pradesh are studied. The vertical trend of the selected elements are defined and possible relationships of these elements to the minerals present in or associated with the above coal are examined. The Gevra Coals have ash contact ( 3 times world average) and low sulphur content (1/4 of world average). Most elements are found to be positively correlated with ash indicating an inorganic association. Elements which show organic affinity include S, Cl, I and In. Fe, Cu, Zn and Pb occur in sulfide phases, the dominant Fe phase identified is siderite which also contain Mn and Mg. Th and U along with varying proportions of rare earths, Ce, Dy, La and Y have been identified with discrete phosphate minerals. Most trace elements have been found to be concentrated in the upper and lower portions of the coal seam exposed in Gevra mine and in partings. It is, therefore, suggested that selective mining and removal of high ash/inorganic material, particularly the upper and lower portion of the seam, will greatly reduce the mobilization of Al, As, Co, Fe, Hf, Sc, Si, Ti and to a lesser degree Cr, La, Mn, Th U and V during combustion of coal in power plants and consequently will reduce the influx of trace elements to the environment. (M.G.B.). 23 refs., 5 figs

Exploring the determinants of health and wellbeing in communities living in proximity to coal seam gas developments in regional Queensland

Directory of Open Access Journals (Sweden)

Fiona Mactaggart

2017-08-01

Full Text Available Abstract Background There is some concern that coal seam gas mining may affect health and wellbeing through changes in social determinants such as living and working conditions, local economy and the environment. The onward impact of these conditions on health and wellbeing is often not monitored to the same degree as direct environmental health impacts in the mining context, but merits attention. This study reports on the findings from a recurrent theme that emerged from analysis of the qualitative component of a comprehensive Health Needs Assessment (HNA conducted in regional Queensland: that health and wellbeing of communities was reportedly affected by nearby coal seam gas (CSG development beyond direct environmental impacts. Methods Qualitative analysis was initially completed using the Framework Method to explore key themes from 11 focus group discussions, 19 in-depth interviews, and 45 key informant interviews with health and wellbeing service providers and community members. A key theme emerged from the analysis that forms the basis of this paper. This study is part of a larger comprehensive HNA involving qualitative and quantitative data collection to explore the health and wellbeing needs of three communities living in proximity to CSG development in regional Queensland, Australia. Results Communities faced social, economic and environmental impacts from the rapid growth of CSG development, which were perceived to have direct and indirect effects on individual lifestyle factors such as alcohol and drug abuse, family relationships, social capital and mental health; and community-level factors including social connectedness, civic engagement and trust. Conclusions Outer regional communities discussed the effects of mining activity on the fabric of their town and community, whereas the inner regional community that had a longer history of industrial activity discussed the impacts on families and individual health and wellbeing. The

Portable rapid gas content measurement - an opportunity for a step change in the coal industry?

International Nuclear Information System (INIS)

Beamish, Basil; Kizil, Mehmet; Gu, Ming

2013-01-01

The last major advance in gas content measurement for coal seams was the introduction of the quick crush technique in the early 1990s. This is a laboratory test method that has proven very reliable over the years. Recent laboratory testing using a portable quick crushing device, known as the portable gas content analyser, has produced consistent gas content results for a set of core samples obtained from a single borehole that intersected four coal seams. The retained gas content values obtained for the seams show the same increasing gas content pattern and gas composition change with depth as the standard quick crush technique. Use of the portable gas content analyser provides the opportunity to produce rapid, reliable gas content measurement of coal that could be developed for assessing gas compliance cores and outburst-prone conditions at a mine site.

Late Cretaceous coal overlying karstic bauxite deposits in the Parnassus-Ghiona Unit, Central Greece: Coal characteristics and depositional environment

Energy Technology Data Exchange (ETDEWEB)

Kalaitzidis, Stavros; Siavalas, George; Christanis, Kimon [Dept. of Geology, University of Patras, 26504 Rio-Patras (Greece); Skarpelis, Nikos [Dept. of Geology and Geoenvironment, University of Athens, 15784 Zografou (Greece); Araujo, Carla Viviane [Petrobras-Cenpes GEOQ/PDEXP, Rua Horacio Macedo n 950, Cidade Universitaria - Ilha do Fundao, 21941-915 Rio de Janeiro (Brazil)

2010-04-01

The Pera-Lakkos coal located on top of bauxite deposits in the Ghiona mining district (Central Greece), is the only known Mesozoic (Late Cretaceous) coal in the country. It was derived from herbaceous plants and algae growing in mildly brackish mires that formed behind a barrier system during a regression of the sea, on a karstified limestone partly filled in with bauxitic detritus. Petrological, mineralogical and geochemical data point to the predominance of reducing conditions and intense organic matter degradation in the palaeomires. O/C vs. H/C and OI vs. HI plots, based on elemental analysis and Rock-Eval data, characterize kerogen types I/II. This reflects the relatively high liptinite content of the coal. Besides kerogen composition, O/C vs. H/C plot for the Pera-Lakkos coals is in accordance with a catagenesis stage of maturation in contrast with vitrinite reflectance and T{sub max} from Rock-Eval pyrolysis, which indicate the onset of oil window maturation stage. Suppression of vitrinite reflectance should be considered and the high liptinite content corroborates this hypothesis. Despite some favourable aspects for petroleum generation presented by the Pera-Lakkos coal, its maximum thickness (up to 50 cm) points to a restricted potential for petroleum generation. Coal oxidation took place either during the late stage of peat formation, due to wave action accompanying the subsequent marine transgression, or epigenetically after the emergence of the whole sequence due to percolation of drainage waters. Both options are also supported by the REE shale-normalized profiles, which demonstrate an upwards depletion in the coal layer. Oxidation also affected pyrite included in the coal; this led to the formation of acidic (sulfate-rich) solutions, which percolated downwards resulting in bleaching of the upper part of the underlying bauxite. (author)

Cuttability of coal

Energy Technology Data Exchange (ETDEWEB)

Sikora, W

1978-01-01

The process of cutting dull M, dull bright MB, bright dull BM, and bright B coal under various compressive stress conditions was studied in laboratory tests. The efficiency of ploughs depends much more on the natural mining conditions than does that of shearer-loaders. For seams of medium workability, it is difficult to forecast whether ploughs will be successful. Cuttability tests are a good way of determining whether ploughs can be used. The effort necessary to cut coal in a stressed condition depends not only on such properties as the workability defined by the Protodyakonov index or compressive strength, but also, and mainly, on the petrographic structure and elastic properties of the coal. In bright coals with high elastic strain, and with BM and MB coals, a much greater increment of effort is necessary with increase in compressive stresses. The cuttability of dull coals from difficult mines was not very different.

CoalVal-A coal resource valuation program

Science.gov (United States)

Rohrbacher, Timothy J.; McIntosh, Gary E.

2010-01-01

CoalVal is a menu-driven Windows program that produces cost-of-mining analyses of mine-modeled coal resources. Geological modeling of the coal beds and some degree of mine planning, from basic prefeasibility to advanced, must already have been performed before this program can be used. United States Geological Survey mine planning is done from a very basic, prefeasibility standpoint, but the accuracy of CoalVal's output is a reflection of the accuracy of the data entered, both for mine costs and mine planning. The mining cost analysis is done by using mine cost models designed for the commonly employed, surface and underground mining methods utilized in the United States. CoalVal requires a Microsoft Windows? 98 or Windows? XP operating system and a minimum of 1 gigabyte of random access memory to perform operations. It will not operate on Microsoft Vista?, Windows? 7, or Macintosh? operating systems. The program will summarize the evaluation of an unlimited number of coal seams, haulage zones, tax entities, or other area delineations for a given coal property, coalfield, or basin. When the reader opens the CoalVal publication from the USGS website, options are provided to download the CoalVal publication manual and the CoalVal Program. The CoalVal report is divided into five specific areas relevant to the development and use of the CoalVal program: 1. Introduction to CoalVal Assumptions and Concepts. 2. Mine Model Assumption Details (appendix A). 3. CoalVal Project Tutorial (appendix B). 4. Program Description (appendix C). 5. Mine Model and Discounted Cash Flow Formulas (appendix D). The tutorial explains how to enter coal resource and quality data by mining method; program default values for production, operating, and cost variables; and ones own operating and cost variables into the program. Generated summary reports list the volume of resource in short tons available for mining, recoverable short tons by mining method; the seam or property being mined

Preparation of coal slurries deposited in ground settling ponds

Directory of Open Access Journals (Sweden)

Wiesław Blaschke

2005-11-01

Full Text Available As a result of the hard coal washing process, considerable quantities of coal slimes are generated. They belong to grain size classes below 1, 0 mm (with the majority of grains below 0,035 mm and are often sold in order to prepare blends for the power generation. It is assessed that in Poland about 11 mln tons of such slimes were deposited. The slimes of a low ash content can be exploited and sold. The slime of high ash content must be washed. In Poland there is one coal preparation plant for slurries. The article describes the technology and presents the results of a simplified economic analysis of exploitation of the slurries and their washing.

Use of natural gamma radiation in the coal mining industry

International Nuclear Information System (INIS)

Wykes, J.S.; Adsley, I.; Cooper, L.R.

1982-01-01

The technique of delineating coal seams by the use of natural gamma borehole logging sondes has been known for many years. The principle of the technique is that the gamma fluxes in shales are higher than in coals as the abundance of naturally occurring radionuclides is some twenty times greater in the former. This paper discusses other applications where the differeing natural gamma properties of coals and shales can be used. These are: (a) To distinguish between stone (shale) and run-of-mine coal on conveyor belts. A common situation underground is one in which stone from development headings and normal run-of-mine coal have to be batched along the same conveyor system. A natural gamma device capable of distinguishing between such batches of material, and thus allowing suitable mechanical separation, will be described. (b) To provide an accurate measurement of roof coal thickness by measuring the natural gamma flux penetrating the roof coal. To illustrate this examples will be given where this technique is used to provide automatic controlled steering of Long Wall Shearers and to provide manually assisted steering of In-seam Heading Machines

Reconstruction of 3D Micro Pore Structure of Coal and Simulation of Its Mechanical Properties

Directory of Open Access Journals (Sweden)

Guang-zhe Deng

2017-01-01

Full Text Available This article takes the low permeability coal seam in the coalfield of South Judger Basin in Xinjiang, as a research object. The pore structure characteristics of coal rock mass in low permeability coal seam were analyzed quantitatively using scanning electron microscopy (SEM through the methods of statistics and digital image analysis. Based on the pore structure parameters and the distribution function of the coal rock mass, a three-dimensional porous cylinder model with different porosity was reconstructed by FLAC3D. The numerical simulation study of reconstructed pore model shows that (1 the porosity and the compressive strength have obvious nonlinear relation and satisfy the negative exponential relation; (2 the porosity significantly affects the stress distribution; with the increase of micro porosity, the stress distribution becomes nonuniform; (3 the compressive failures of different models are mainly shear failures, and the shape of fracture section is related to porosity; (4 the variation of seepage coefficient of the pore reconstruction model is consistent with the development of micro cracks. The micro mechanism of the deformation and failure of coal and the interaction of multiphase flow with porosity are revealed, which provides a theoretical reference for the clean development of the low permeability coal seam.

Methane emissions from coal mining

International Nuclear Information System (INIS)

Boyer, C.M.; Kelafant, J.R.; Kuuskraa, V.A.; Manger, K.C.; Kruger, D.

1990-09-01

The report estimates global methane emissions from coal mining on a country specific basis, evaluates the technologies available to degasify coal seams and assesses the economics of recovering methane liberated during mining. 33 to 64 million tonnes were liberated in 1987 from coal mining, 75 per cent of which came from China, the USSR, Poland and the USA. Methane emissions from coal mining are likely to increase. Emission levels vary between surface and underground mines. The methane currently removed from underground mines for safety reasons could be used in a number of ways, which may be economically attractive. 55 refs., 19 figs., 24 tabs

Regional trend of coal metamorphism in the major Gondwana basins of India

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, A K; Alam, M M; Bunerjee, B

1983-04-01

The coal-bearing Gondwana sedimentaries are of great economic importance as they possess over 98% of coal resources of India. Within the Gondwana supergroup coal-bearing formations are confined in the Lower Gondwana sequence (Damuda group). The development of coal seams in the different basins were genetically related to the evolutionary pattern of each basin. The imprint of such diverse tectono-geomorphic conditions prevailing over the vast Peninsular Shield, and their regional impact in individual basins are well preserved in the different lithofacies of this thick-pile of sedimentary sequence. In fact constituting coal facies served as a sensitive recorder of the past episode enacted for long geological time span in each basin of the Gondwana grabens. In the present paper an attempt is made to incorporate the salient features of the operative processes in the major Gondwana basins with special reference to coal metamorphism. This has been done considering mass of analytical and sub-surface data available from the physico-chemical survey of coal seams of major coalfields, and extensive drilling operations carried out over the vast virgin tracts of important coalfields.

The application of a coupled artificial neural network and fault tree analysis model to predict coal and gas outbursts

Energy Technology Data Exchange (ETDEWEB)

Ruilin, Zhang [School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo, Henan Province, 454003, PR (China); Lowndes, Ian S. [Process and Environmental Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom)

2010-11-01

This paper proposes the use of a coupled fault tree analysis (FTA) and artificial neural network (ANN) model to improve the prediction of the potential risk of coal and gas outburst events during the underground mining of thick and deep Chinese coal seams. The model developed has been used to investigate the gas emission characteristics and the geological conditions that exist within the Huaibei coal mining region, Anhui province, China. The coal seams in this region exhibit a high incidence of coal and gas outbursts. An analysis of the results obtained from an initial application of an FTA model, identified eight dominant model parameters related to the gas content or geological conditions of the coal seams, which characterize the potential risk of in situ coal and gas outbursts. The eight dominant model parameters identified by the FTA method were subsequently used as input variables to an ANN model. The results produced by the ANN model were used to develop a qualitative risk index to characterize the potential risk level of occurrence of coal and gas outburst events. Four different potential risk alarm levels were defined: SAFE, POTENTIAL, HIGH and STRONG. Solutions to the prediction model were obtained using a combination of quantitative and qualitative data including the gas content or gas pressure and the geological and geotechnical conditions of coal seams. The application of this combined solution method identified more explicit and accurate model relationships between the in situ geological conditions and the potential risk of coal and gas outbursts. An analysis of the model solutions concluded that the coupled FTA and ANN model may offer a reliable alternative method to forecast the potential risk of coal and gas outbursts. (author)

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 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.

Leslie Cemetery and Francisco distributary fluvial channels in the Petersburg Formation (Pennsylvanian) of Gibson County, Indiana, USA

Energy Technology Data Exchange (ETDEWEB)

Eggert, D L

1984-01-01

The Leslie Cemetery Channel is a small distributary fluvial channel that is partly contemporaneous with the Springfield Coal member of the Petersburg Formation (Pennsylvanian) and splits the seam into two seams. This channel is 1-6 miles (1.6-10 km) wide and extends 30 miles (48 km) in the subsurface. Overbank and channel fill deposits consisting of sandstone, siltstone, and mudstone split the coal into two seams up to 40-50 ft (12-15 m) apart in places. The lower seam is a low-sulphur coal. Adjacent to this channel is the unsplit coal, which is as much as 9 ft (3 m) thick. Beneath the Leslie Cemetery Channel and the Springfield coal is the slightly older Francisco Channel (new name), which is younger than the next lower coal. This channel is filled with a fining-upward sandstone as much as 75 ft (23 m) thick. The positions of these stacked channels were determined by the differential compaction of earlier sediments. 20 references.

A novel method for estimating methane emissions from underground coal mines: The Yanma coal mine, China

Science.gov (United States)

Ji, Zhong-Min; Chen, Zhi-Jian; Pan, Jie-Nan; Niu, Qing-He

2017-12-01

As the world's largest coal producer and consumer, China accounts for a relatively high proportion of methane emissions from coal mines. Several estimation methods had been established for the coal mine methane (CMM) emission. However, with large regional differences, various reservoir formation types of coalbed methane (CBM) and due to the complicated geological conditions in China, these methods may be deficient or unsuitable for all the mining areas (e.g. Jiaozuo mining area). By combing the CMM emission characteristics and considering the actual situation of methane emissions from underground coal mine, we found that the methane pre-drainage is a crucial reason creating inaccurate evaluating results for most estimation methods. What makes it so essential is the extensive pre-drainage quantity and its irrelevance with annual coal production. Accordingly, the methane releases were divided into two categories: methane pre-drainage and methane release during mining. On this basis, a pioneering method for estimating CMM emissions was proposed. Taking the Yanma coal mine in the Jiaozuo mining area as a study case, the evaluation method of the pre-drainage methane quantity was established after the correlation analysis between the pre-drainage rate and time. Thereafter, the mining activity influence factor (MAIF) was first introduced to reflect the methane release from the coal and rock seams around where affected by mining activity, and the buried depth was adopted as the predictor of the estimation for future methane emissions. It was verified in the six coal mines of Jiaozuo coalfield (2011) that the new estimation method has the minimum errors of 12.11%, 9.23%, 5.77%, -5.20%, -8.75% and 4.92% respectively comparing with other methods. This paper gives a further insight and proposes a more accurate evaluation method for the CMM emissions, especially for the coal seams with low permeability and strong tectonic deformation in methane outburst coal mines.

Energy generation potential from coals of the Charqueadas Coalfield, RS, Brazil

Science.gov (United States)

Correa da Silva, Z. C.; Heemann, R.; Castro, L.; Ketzer, J. M.

2009-04-01

Three coal seams, I2B (Inferior 2), I1F (Inferior 1) and MB, from the Charqueadas Coalfield located in the central-east region of the State of Rio Grande do Sul, Southern Brazil were studied on the basis of geological, petrographic, chemical and geochemical techniques and correlated to the SR1, SR2 and SR3 coal seams from the Santa Rita Coalfield. The Charqueadas Coalfield reserves reach 2,993x106 metric tons of coal distributed in six coal seams. The study of sedimentary and organic facies is made on the subsurface data from five boreholes drilled in the area. There show a well marked lateral facies change from sub aquatic to sub aerial environment, conditioned by both the water level variations and the irregular palaeotopography of the basement. The coals change from limnic to forest-terrestrial moor types characterized by variations of composition in terms of macerals, microlithotypes and mineral matter. The coals are rich in mineral matter (28 to 40%); the vitrinite content reaches 50 %, inertinite 44 % and liptinite varies from 10 to 30 %, in mineral matter free basis. Among the microlithotypes carbominerite and vitrite are predominant. Rank studies carried out by different methods (vitrinite reflectance, max and red-green quotient among others) gave conflicting results, which are explained by the strong bituminization of the vitrinite. However, agreement between fluorescence measurements and organic geochemical parameters (e.g. CPI values) confirm that the coals are of a High Volatile Bituminous B/C (ASTM) or Gasflammkohle (DIN) rank. Based on these characteristics, the Charqueadas coal seams show great potential for use in Underground Coal Gasification (UCG) and Enhanced Coalbed Methane (ECBM) projects. Nowadays the state of Rio Grande do Sul is rapidly growing and needs to increase the energy efficiency to attend the industrial demands, filling the gap between supply and energy generation. As with conventional IGCC, UCG gas can be used to generate

FY 1997 basic survey for coal resource development. Data collection of the joint research of new technology in the geophysical exploration of coal resources (water area medium depth seam survey); 1997 nendo sekitan shigen kaihatsu kiso chosa shiryoshu. Shintansa gijutsu chosa kaihatsu (suiiki chushindoso tansa)

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

In 'the new exploration technology test on coal resource' (water area medium depth seam exploration) jointly conducted between Japan and China, tests have been carried out for 5 years on the BDR-5 test boring measurement monitoring system and the diamond bit which are items of the technology development of high resolution seismic survey system and high efficiency test boring system. As a result, the new technology test was successful, and technical economic effects were obtained. The situation of the test was summarized. The following data were compiled as shown in Data No.1-12. 1. The proceedings of the FY 1997 Japan-China steering committee (No.9). 2. Report on the survey of China verification field South Sihu water level situation. 3. The proceedings of the FY 1997 Japan-China steering committee (final). 4. Report on the FY 1997 reflection seismic exploration survey. 5. Report on the FY 1997 No.2 test boring survey. 6. Summarization of the test on 'the new exploration technology of coal source' conducted between Japan and China. 7. Report on the drilling data measurement. 8. Various sections of the reflection seismic survey data processing. 9. Traverse line chart. 10. T3 isochrone chart. 11. T3 depth structural chart. 12. Report on the new exploration technology survey development (water area medium depth seam exploration) geological model making. (NEDO)

The underground coal gasification First step of community collaboration; Gasification Subterranea del Carbon. Primer Intento en el Ambito de una Colaboracion Comunitaria

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

The objective of the project was to demonstrate the technical feasibility of underground coal gasification in coal seams at 600 metre depth, in order to asses its potential as a means of energy exploitation in Europe. The trial was based on the use of deviated boreholes and a retractable injection system techniques, which have both been developed by the oil and gas industries. One borehole, the injection well, was drilled in the coal seam. The other, the vertical production well, was run to intercept it in the lower part of the coal seam as closely as possible, in order to construct a continuous channel for gasification. The well were completed with casing and concentric tubing to provide the necessary paths for production, injection, purging gas and cooling water flows. A coiled tubing located in the injection well was used to execute the retraction (or CRIP) manoeuvre, which is a process in which the injector head for the gasification agents, i. e. oxygen and water, and the ignitor, are directed to a specific section of the coal seam. The gasification products passes to a surface production line for flow measurement and sampling of gas and condensate products. Production gases were either flared or incinerated, while the liquids were collected for appropriate disposal. The first trial achieved its principal objectives of in seam drilling, channel communication, the CRIP manoeuvres and the gasification of significant quantity of coal. The post-gasification study also identified the shape and extent of the cavity. The study has demonstrated the technical feasibility of underground coal gasification at the intermediate depths of European coal and proposals are made for further development and semi-commercial exploitation of this promising extraction technology. (Author) 11 refs.

Full Scale Deposition Trials at 150 MWe PF-boiler Co-firing COal and Straw: Summary of Results

DEFF Research Database (Denmark)

Andersen, Karin Hedebo; Frandsen, Flemming; Hansen, Peter Farkas Binderup

1999-01-01

A conventional PF-fired boiler at the Danish energy company I/S Midtkraft has been converted to coal-straw co-combustion and a two-year demonstration programme was initiated in January 1996 addressing several aspects of coal-straw co-combustion. Deposition trials were performed as part...... during co-combustion with straw. In addition, where Fe dominated upstream deposits are found in the hottest positions during pure coal combustion, Ca, and to some degree Si, are playing the major role during co-combustion. The addition of straw to the fuel is also seen to lead to a change in the texture...... of the upstream deposits, from an ordered dendritic structure of the larger particles with small particles in between during pure coal combustion, to a more random deposition of the larger particles among the small during co-combustion. No deposition of chlorine species was observed in the SEM-EDX analysis...

Depositional history of the Fire Clay coal bed (Late Duckmantian), Eastern Kentucky, USA

Science.gov (United States)

Greb, S.F.; Eble, C.F.; Hower, J.C.

1999-01-01

More than 3800 coal thickness measurements, proximate analyses from 97 localities, and stratigraphic and sedimentological analyses from more than 300 outcrops and cores were used in conjunction with previously reported palynological and petrographic studies to map individual benches of the coal and document bench-scale variability in the Fire Clay (Hazard No. 4) coal bed across a 1860 km2 area of the Eastern Kentucky Coal Field. The bench architecture of the Fire Clay coal bed consists of uncommon leader benches, a persistent but variable lower bench, a widespread, and generally thick upper bench, and local, variable rider benches. Rheotrophic conditions are inferred for the leader benches and lower bench based on sedimentological associations, mixed palynomorph assemblages, locally common cannel coal layers, and generally high ash yields. The lower bench consistently exhibits vertical variability in petrography and palynology that reflects changing trophic conditions as topographic depressions infilled. Infilling also led to unconfined flooding and ultimately the drowning of the lower bench mire. The drowned mire was covered by an air-fall volcanic-ash deposit, which produced the characteristic flint clay parting. The extent and uniform thickness of the parting suggests that the ash layer was deposited in water on a relatively flat surface without a thick canopy or extensive standing vegetation across most of the study area. Ash deposits led to regional ponding and establishment of a second planar mire. Because the topography had become a broadly uniform, nutrient-rich surface, upper-bench peats became widespread with large areas of the mire distant to clastic sources. Vertical sections of thick (> 70 cm), low-ash yield, upper coal bench show a common palynomorph change from arborescent lycopod dominance upward to fern and densospore-producing, small lycopod dominance, inferred as a shift from planar to ombrotrophic mire phases. Domed mires appear to have been

Mine Water Treatment in Hongai Coal Mines

OpenAIRE

Dang Phuong Thao; Dang Vu Chi

2018-01-01

Acid mine drainage (AMD) is recognized as one of the most serious environmental problem associated with mining industry. Acid water, also known as acid mine drainage forms when iron sulfide minerals found in the rock of coal seams are exposed to oxidizing conditions in coal mining. Until 2009, mine drainage in Hongai coal mines was not treated, leading to harmful effects on humans, animals and aquatic ecosystem. This report has examined acid mine drainage problem and techniques for acid mine ...

Log evaluation of sub-bituminous coals in Magallanes, Chile

International Nuclear Information System (INIS)

Weltz, L.S.

1976-01-01

In coal exploration a drilling program is normally used for coal inquest through core analysis, with a high cost and operating time. However, in many cases, there is poor cores recovery due to operating procedures and/or formation conditions which leads to the determination of parameters non-representative of the coal seam. The cost and operating time can be minimized through the use of logs which also represent a continuous and in situ sampling. In the case of sub-bituminous coals, the analysis through logs is more complex due to the high content of clay, which masks the presence of water. This paper describes the analysis of sub-bituminous coals in Magallanes-Chile. The main coal seam components are: coal, clay, secondary quartz and water. An interpretation system using the density log, gamma ray, sonic and microlog, based on rho/sub B/-GR and rho/sub B/--Δ/sub T/ cross plots, permits to know the weight percentages of the following elements: total carbon, ash, moisture, which form the main local coal parameters. Empirical relationships permit us to obtain also the heating value and an estimate strength index to elastic-dynamic forces. The results obtained agree within 3 percent with the Laboratory cores analysis. The method is processed through a sequence of simple computer programs for IBM-360

Overall requirements for an advanced underground coal extraction system. [environment effects, miner health and safety, production cost, and coal conservation

Science.gov (United States)

Goldsmith, M.; Lavin, M. L.

1980-01-01

Underground mining systems suitable for coal seams expoitable in the year 2000 are examined with particular relevance to the resources of Central Appalachia. Requirements for such systems may be summarized as follows: (1) production cost; (2)miner safety; (3) miner health; (4) environmental impact; and (5) coal conservation. No significant trade offs between production cost and other performance indices were found.

Sorption characteristic of coal as regards of gas mixtures emitted in the process of the self-heating of coal

Directory of Open Access Journals (Sweden)

Wojtacha-Rychter Karolina

2017-01-01

Full Text Available One of the most challenging tasks in the coal mining sector is the detection of endogenous fire risks. Under field conditions, the distance between the points where samples for the analyses are collected and the actual place where coal self-heating takes place may be quite remote. Coal is a natural sorbent with a diverse character of pore structures which are surrounded by fractures and cleavage planes constituting ideal spaces for the flow and adsorption of gases. The gases (methane, ethane, ethylene, propane, propylene, acetylene, carbon dioxide, carbon monoxide, hydrogen released from the source of fire migrate through the seam and may be subject to adsorption, or they may cause the desorption of gases accumulated in coal. Therefore, the values of reference sample concentrations may be overstated or understated, respectively. The objective of this experimental study was to investigate the adsorption phenomena accompanying the flow of a multi-component gas mixture through a coal bed which may occur in situ. The research was conducted by means of a method based on a series of calorimetric/chromatographic measurements taken to determine the amount of gases released during coal heating at various temperatures under laboratory conditions. Based on the results obtained in the course of the experiments, it was concluded that the amount of gas adsorbed in the seam depends on the type of coal and the gas. Within the multi-component gas mixture, hydrocarbons demonstrated the largest sorption capacity, especially as concerns propylene.

Testing the shearer-loader EDW 170/200 ln for thin seams in connection with chainless haulage. Final report

Energy Technology Data Exchange (ETDEWEB)

Tegenthoff, J.; Klimek, K.H.

1982-01-01

Coal extraction by cutting was investigated. A low clearance machine design was tested. To decrease average seam thickness, a system able to operate in a seam aperture of approximately 1.7 m was needed. Maximum possible clearance above the machine was sought, while maintaining sufficient clearance underneath the machine for haulage. A machine height of 855 mm with underbody clearance of 475 mm was achieved. The drive performance and traction force of the winch require improvement. For better utilization of machine potential, a rotational angle should be adapted to the positioning of the drum cutters. (ESA)

Physico-chemical properties of clay deposits of Bina and Jhingurdah mines of Singrauli coalfield, District Sidhi (MP)

Energy Technology Data Exchange (ETDEWEB)

Singh, V B; Joshi, V C

1980-01-01

Clay samples exposed over Baraker and Raniganj coal seams of Lower Gondwana System in Bina and Jhingurdah mines respectively are studied. The chemical and rational analyses of the samples indicate that range of variation of the different constituents. Infra-red, X-ray diffraction, differential thermal analysis and thermal gravimetric analysis were used to determine clay and other minerals. The deposits may be suitable for manufacture of triaxial wares, e.g. ordinary porcelain sanitary ware, stoneware, etc.

Optimization of coal recovery from open pits

Energy Technology Data Exchange (ETDEWEB)

Kim, C; Wolff, S F; Baafi, E Y; Cervantes, J A; Coates, D F

1979-02-01

The design techniques of the Pit Slope Manual were successfully applied in a case study concerned with optimizing the design of coal mines. A steeply dipping multiple seam deposit, being mined by the truck-shovel combination, was selected for the study. The criterion for optimum slopes was based on the financial consequences of each design, i.e., the resultant benefits and costs. Three alternative designs were analyzed. The first had an average highwall slope angle of 28 degrees and a final height of 290 m. The second had a 35 degrees slope angle and a 305-m wall height. The third had a 45 degrees slope angle and a 320-m wall height. Trade-off between benefits and increased cost of slope instability inherent in steeper slope angles was analyzed for the entire mine life through computer simulation of actual mining operations. The cost models developed were (1) No Cost, (2) Clean-up, (3) Lost Coal, (4) Early Mining, (5) Mine Abandonment, (6) Increased Haulage, and (7) Haul Road Re-establishment. (8 refs.)

Trace and major metal abundances in the shale and coal of various ...

African Journals Online (AJOL)

The distribution of a number of trace and major elements in the shale and coal of differing seams in Okaba, Kogi State, Nigeria, was studied using energy dispersive x-ray fluorescence spectrometer. The study was necessary to compare the quality of Okaba coal to world standards of coal quality. Major elements of Al, K, Ca ...

Rock mechanics investigations of structural stability in the Bulli seam at West Cliff Colliery

Energy Technology Data Exchange (ETDEWEB)

Jaggar, F

1978-03-01

Rock mechanics investigations were conducted at West Cliff colliery to obtain rock properties and stress measurements and study the stability of mining structures. The roof and floor were drilled in order to obtain core for rock testing and lump samples of coal were collected in order to measure the coal properties. Absolute stress measurements were obtained using CSIR cells. The strata were sufficiently uniform and competent to overcore the emplaced cells. Testing revealed that the rocks were better than average for coal measure sedimentary strata and the stresses indicated the existence of a moderately high horizontal stress field. The coal is of average strength only with some marked variation relating to the very banded nature of the seam. Finite element analyses showed that the rectangular roadways driven using roof bolts and timber supports were stable and adequately stable by an indicative factor of safety of about l.5.

Mine Water Treatment in Hongai Coal Mines

Science.gov (United States)

Dang, Phuong Thao; Dang, Vu Chi

2018-03-01

Acid mine drainage (AMD) is recognized as one of the most serious environmental problem associated with mining industry. Acid water, also known as acid mine drainage forms when iron sulfide minerals found in the rock of coal seams are exposed to oxidizing conditions in coal mining. Until 2009, mine drainage in Hongai coal mines was not treated, leading to harmful effects on humans, animals and aquatic ecosystem. This report has examined acid mine drainage problem and techniques for acid mine drainage treatment in Hongai coal mines. In addition, selection and criteria for the design of the treatment systems have been presented.

GIS Representation of Coal-Bearing Areas in Africa

Science.gov (United States)

Merrill, Matthew D.; Tewalt, Susan J.

2008-01-01

The African continent contains approximately 5 percent of the world's proven recoverable reserves of coal (World Energy Council, 2007). Energy consumption in Africa is projected to grow at an annual rate of 2.3 percent from 2004 through 2030, while average consumption in first-world nations is expected to rise at 1.4 percent annually (Energy Information Administration, 2007). Coal reserves will undoubtedly continue to be part of Africa's energy portfolio as it grows in the future. A review of academic and industrial literature indicates that 27 nations in Africa contain coal-bearing rock. South Africa accounts for 96 percent of Africa's total proven recoverable coal reserves, ranking it sixth in the world. This report is a digital compilation of information on Africa's coal-bearing geology found in the literature and is intended to be used in small scale spatial investigations in a Geographic Information System (GIS) and as a visual aid for the discussion of Africa's coal resources. Many maps of African coal resources often include points for mine locations or regional scale polygons with generalized borders depicting basin edges. Point locations are detailed but provide no information regarding extent, and generalized polygons do not have sufficient detail. In this dataset, the polygons are representative of the actual coal-bearing lithology both in location and regional extent. Existing U.S. Geological Survey (USGS) digital geology datasets provide the majority of the base geologic polygons. Polygons for the coal-bearing localities were clipped from the base geology that represented the age and extent of the coal deposit as indicated in the literature. Where the 1:5,000,000-scale geology base layer's ages conflicted with those in the publications, polygons were generated directly from the regional African coal maps (1:500,000 scale, approximately) in the published material. In these cases, coal-bearing polygons were clipped to the literature's indicated coal

Study on Seam Deformation and Permeability Improved Effect of Pressure Released Mining in Protective Seam%保护层卸压开采煤层变形与增透效应研究

Institute of Scientific and Technical Information of China (English)

涂敏; 袁亮; 缪协兴; 刘泽功; 徐乃忠; 付宝杰

2013-01-01

为了研究高瓦斯赋存煤层卸压增透效应,以达到提高低渗透性松软煤层瓦斯抽采率,降低工作面瓦斯突出危险性,采用RFPA2D-Gasflow软件分析下保护层卸压开采后上覆煤岩采动裂隙发育、应力分布特征及由此产生的卸压煤层增透效应.结果表明:卸压开采煤层的透气性系数增大200倍左右,增透效果显著.利用该研究结果在顾桥矿沿空留巷内布置斜向上长短穿层钻孔,代替传统的底板巷内布置向上穿层钻孔抽采本层采空区内和上覆卸压煤层内瓦斯,可使沿空留巷中回风流和上隅角瓦斯体积分数均控制在0.5％以下,平均瓦斯抽采率达50％ ～ 70％,保证了工作面的安全回采.%In order to study the pressure released and permeability improved effect of the high gas content seam and to reach the targets to improve the gas drainage rate of the low permeability soft seam and to reduce the gas outburst danger of the coal mining face,the RFPA -Gasflow software was applied to analyze the mining crack development and the stress distribution features of the overburden coal and rock and thus created pressure released and permeability effect after the pressure released mining in the underneath protective seam.The results showed that the permeability coefficient of the pressure released mining seam could be increased about 200 times and the permeability improved effect was obvious.The study results were applied to the layout of the inclined upward long and short boreholes in the gateway retained along goaf in Guqiao Mine to replace the layout of the inclined upward borehole in the conventional floor gateway for the gas drainage in the mining goaf and the overburden pressure released seam.Thus the gas volume fractions of the air returning flow in the gateway retained and the gas in the upper corner both could be controlled below 0. 5%, the average gas drainage rate could be 50% ~ 70% and the safety mining of the coal mining face

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.

Relationships between coal-quality and organic-geochemical parameters: A case study of the Hafik coal deposits (Sivas Basin, Turkey)

Energy Technology Data Exchange (ETDEWEB)

Erik, N. Yalcin; Sancar, S. [Cumhuriyet University, Department of Geological Engineering, Sivas (Turkey)

2010-09-01

This study provides coal-quality, organic-petrographic and organic-geochemical data on Tertiary subbituminous coal of the Hafik area, northwestern part of the Sivas Basin, Turkey. Coal-petrological studies along with proximate and ultimate analyses were undertaken to determine the organic-petrographic characteristics of the Hafik coals. Huminite reflectances were found to be between 0.38 and 0.48% (corresponding to an organic-material-rich and coal layers), values characteristic of low maturity. This parameter shows a good correlation with calorific values (average 21,060 kJ/kg) and average T{sub max} (422 C) mineral-matter diagenesis, indicating immaturity. The studied coals and organic material underwent only low-grade transformation, a consequence of low lithostatic pressure. Therefore, the Hafik coals are actually subbituminous in rank. Rock-Eval analysis results show types II/III and III kerogens. The organic fraction of the coals is mostly comprised of humic-group macerals (gelinites), with small percentages derived from the inertinite and liptinite groups. In this study, organic-petrographic, organic-geochemical and coal quality data were compared. The Hafik deposit is a high-ash, high-sulfur coal. The mineral matter of the coals is comprised mainly of calcite and clay minerals. (author)

Slagging behavior of upgraded brown coal and bituminous coal in 145 MW practical coal combustion boiler

Energy Technology Data Exchange (ETDEWEB)

Akiyama, Katsuya; Pak, Haeyang; Takubo, Yoji [Kobe Steel, Ltd, Kobe (Japan). Mechanical Engineering Research Lab.; Tada, Toshiya [Kobe Steel, Ltd, Takasago (Japan). Coal and Energy Technology Dept.; Ueki, Yasuaki [Nagoya Univ. (Japan). Energy Science Div.; Yoshiie, Ryo; Naruse, Ichiro [Nagoya Univ. (Japan). Dept. of Mechanical Science and Engineering

2013-07-01

The purpose of this study is to quantitatively evaluate behaviors of ash deposition during combustion of Upgraded Brown Coal (UBC) and bituminous coal in a 145 MW practical coal combustion boiler. A blended coal consisting 20 wt% of the UBC and 80 wt% of the bituminous coal was burned for the combustion tests. Before the actual ash deposition tests, the molten slag fractions of ash calculated by chemical equilibrium calculations under the combustion condition was adopted as one of the indices to estimate the tendency of ash deposition. The calculation results showed that the molten slag fraction for UBC ash reached approximately 90% at 1,523 K. However, that for the blended coal ash became about 50%. These calculation results mean that blending the UBC with a bituminous coal played a role in decreasing the molten slag fraction. Next, the ash deposition tests were conducted, using a practical pulverized coal combustion boiler. A water-cooled stainless-steel tube was inserted in locations at 1,523 K in the boiler to measure the amount of ash deposits. The results showed that the mass of deposited ash for the blended coal increased and shape of the deposited ash particles on the tube became large and spherical. This is because the molten slag fraction in ash for the blended coal at 1,523 K increased and the surface of deposited ash became sticky. However, the mass of the deposited ash for the blended coal did not greatly increase and no slagging problems occurred for 8 days of boiler operation under the present blending conditions. Therefore, appropriate blending of the UBC with a bituminous coal enables the UBC to be used with a low ash melting point without any ash deposition problems in a practical boiler.

Performance of mesh seam welds in tailor welded blanks; Terado blank yo mash seam yosetsubu no tokusei

Energy Technology Data Exchange (ETDEWEB)

Uchihara, M; Takahashi, M; Kurita, M; Hirose, Y; Fukui, K [Sumitomo Metal Industries, Ltd., Osaka (Japan)

1997-10-01

Formability, fatigue properties and corrosion behavior of mash seam welded steel sheets were investigated and the results were compared with laser weld. The stretch formability of mash seam weld and laser weld were same level. Mash seam weld however, showed slightly smaller formability in hole expansion test. The fatigue strength of mash seam welds was lower than that of laser welds in case of differential thickness joints. Corrosion was apt to initiate at weld in both mash seam and laser weld with E-coat. The corrosion resistance of welds was improved by using zinc coated steel. 3 refs., 14 figs., 2 tabs.

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.)

Longwall top coal caving (LTCC) mining technologies with roof softening by hydraulic fracturing method

Science.gov (United States)

Klishin, V.; Nikitenko, S.; Opruk, G.

2018-05-01

The paper discusses advanced top coal caving technologies for thick coal seams and addresses some issues of incomplete coal extraction, which can result in the environmental damage, landscape change, air and water pollution and endogenous fires. The authors put forward a fundamentally new, having no equivalent and ecology-friendly method to difficult-to-cave roof coal – directional hydraulic fracturing and nonexplosive disintegration.

A novel weld seam detection method for space weld seam of narrow butt joint in laser welding

Science.gov (United States)

Shao, Wen Jun; Huang, Yu; Zhang, Yong

2018-02-01

Structured light measurement is widely used for weld seam detection owing to its high measurement precision and robust. However, there is nearly no geometrical deformation of the stripe projected onto weld face, whose seam width is less than 0.1 mm and without misalignment. So, it's very difficult to ensure an exact retrieval of the seam feature. This issue is raised as laser welding for butt joint of thin metal plate is widely applied. Moreover, measurement for the seam width, seam center and the normal vector of the weld face at the same time during welding process is of great importance to the welding quality but rarely reported. Consequently, a seam measurement method based on vision sensor for space weld seam of narrow butt joint is proposed in this article. Three laser stripes with different wave length are project on the weldment, in which two red laser stripes are designed and used to measure the three dimensional profile of the weld face by the principle of optical triangulation, and the third green laser stripe is used as light source to measure the edge and the centerline of the seam by the principle of passive vision sensor. The corresponding image process algorithm is proposed to extract the centerline of the red laser stripes as well as the seam feature. All these three laser stripes are captured and processed in a single image so that the three dimensional position of the space weld seam can be obtained simultaneously. Finally, the result of experiment reveals that the proposed method can meet the precision demand of space narrow butt joint.

Social licence, corporate social responsibility and coal seam gas: framing the new political dynamics of contestation

International Nuclear Information System (INIS)

Curran, Giorel

2017-01-01

This paper explores the contestation dynamics between the unconventional gas mining sector and its challengers through the prism of the social licence to operate. Social licence is a dominant narrative in the mining sector today and as a signifier of the sector's CSR credentials, the term is an influential one. Its capacity to confer project legitimacy, and hence avoid the risks of community opposition, helps explain why most companies seek to gain one. Today both gas proponents and opponents talk the language of social licence: the former to defend their projects, the latter to challenge them. Yet, beyond rhetoric, the precise meaning of social licence remains elusive. This paper uses a case study of community opposition to primarily coal seam gas projects in an eastern Australian region to explore how the absence of a precise meaning for social licence has created a strategic opportunity space for the industry's opponents to invest social licence with a potent democracy frame. This democracy framing has proved particularly effective as a contestation tool and helps explain the outcomes in this case. - Highlights: • Unconventional gas exploration and mining is becoming increasingly contested. • A key way of managing this contestation is through the social licence to operate. • Both proponents and opponents of gas mining use social licence strategically. • Social licence has become increasingly politicised. • A democratic frame assists the effectiveness of contestation.

An isotopic study of the role of carbon dioxide in outbursts in coal mines

International Nuclear Information System (INIS)

Smith, J.W.; Gould, K.W.

1980-01-01

The occurrence of instantaneous outbursting in the Bulli coal seam at the West Cliff Colliery, Appin, NSW can be correlated directly with an increase in concentration (0.5 to 75%) and a related decrease in the 13 C content (delta 13 C + 16 to -0.8% PDB) of the CO 2 in the seam gas. Two sources of CO 2 are required. The greater incidence of outbursting in CO 2 -rich zones is explained by the conversion to bicarbonate of cleat and fracture filling calcite deep within the coal and the transport of this bicarbonate in water to mine openings. The weakening of the resistance of the coal to shear by this removal of carbonate is an additional factor to be considered in assessing outbursting situations. (author)

Berau coal in East Kalimantan; Its petrographics characteristics and depositional environment

Directory of Open Access Journals (Sweden)

Nana Suwarna

2014-06-01

Full Text Available http://dx.doi.org/10.17014/ijog.vol2no4.20071To asses the characteristics of the Early to Middle Miocene Berau coal in the Berau Basin, leading to interpretation of coal depositional environments, some fresh outcrop and subcrop samples and also drill cores of the coals have been analyzed microscopically. Coal petrographic analysis was performed on twenty four coal samples from the Middle Miocene Lati Formation. Vitrinite, present in a high value, and ranging between 66.2 - 96.2%, is dominated by vitrinite B. On the other hand, inertinite and exinite, showing a similar value, exist in a low to moderate amount. Vitrinite reflectance, present in a low value, varies from 0.40 - 0.58%. Low mineral matter content is dominated by clay minerals (0.4 - 6.6% with minor pyrite. Transitions from wet and very wet forested swamps to drier conditions with lower tree density are indicated by the higher content of vitrinite B, whilst a reverse trend is indicated by the lower content of vitrinite A. Petrographic indices obtained from facies diagnostic macerals show that an accumulation of the ancient peats under prevailing relatively wet limited influx clastic marsh to very wet forest swamps or moors is considered. The composition of the coal samples supports the interpretation of a system of fluvial to meandering streams in an upper delta plain environment. The original peat-forming vegetation was composed mainly of cellulose rich, shrub-like plants, tree ferns, herbaceous plant communities, with minor amount of trees. Thereby, the organic facies concept is thus applicable in basin studies context and has potential to become an additional tool for depositional environment interpretation.  

Soil as an archive of coal-fired power plant mercury deposition.

Science.gov (United States)

Rodríguez Martín, José Antonio; Nanos, Nikos

2016-05-05

Mercury pollution is a global environmental problem that has serious implications for human health. One of the most important sources of anthropogenic mercury emissions are coal-burning power plants. Hg accumulations in soil are associated with their atmospheric deposition. Our study provides the first assessment of soil Hg on the entire Spanish surface obtained from one sampling protocol. Hg spatial distribution was analysed with topsoil samples taken from 4000 locations in a regular sampling grid. The other aim was to use geostatistical techniques to verify the extent of soil contamination by Hg and to evaluate presumed Hg enrichment near the seven Spanish power plants with installed capacity above 1000 MW. The Hg concentration in Spanish soil fell within the range of 1-7564 μg kg(-1) (mean 67.2) and 50% of the samples had a concentration below 37 μg kg(-1). Evidence for human activity was found near all the coal-fired power plants, which reflects that metals have accumulated in the basin over many years. Values over 1000 μg kg(-1) have been found in soils in the vicinity of the Aboño, Soto de Ribera and Castellon power plants. However, soil Hg enrichment was detectable only close to the emission source, within an approximate range of only 15 km from the power plants. We associated this effect with airborne emissions and subsequent depositions as the potential distance through fly ash deposition. Hg associated with particles of ash tends to be deposited near coal combustion sources. Copyright © 2016 Elsevier B.V. All rights reserved.

Mine Water Treatment in Hongai Coal Mines

Directory of Open Access Journals (Sweden)

Dang Phuong Thao

2018-01-01

Full Text Available Acid mine drainage (AMD is recognized as one of the most serious environmental problem associated with mining industry. Acid water, also known as acid mine drainage forms when iron sulfide minerals found in the rock of coal seams are exposed to oxidizing conditions in coal mining. Until 2009, mine drainage in Hongai coal mines was not treated, leading to harmful effects on humans, animals and aquatic ecosystem. This report has examined acid mine drainage problem and techniques for acid mine drainage treatment in Hongai coal mines. In addition, selection and criteria for the design of the treatment systems have been presented.

Deposit formation in a full-scale pulverized wood-fired power plant with and without coal fly ash addition

DEFF Research Database (Denmark)

Wu, Hao; Shafique Bashir, Muhammad; Jensen, Peter Arendt

2013-01-01

Ash transformation and deposition in a pulverized wood-fired power plant boiler of 800 MWth were studied with and without the addition of coal fly ash. The transient ash deposition behavior was investigated by using an advanced deposit probe system at two different boiler locations with flue gas...... at the low-temperature location showed a slow initial build-up and a stable mass of deposits after approximately 1-5 h. The deposits collected during pulverized wood combustion contained a considerable amount of K2SO4, KCl, and KOH/K2CO3. With the addition of coal fly ash (~4 times of the mass flow of wood...... ash) to the boiler, these alkali species were effectively removed both in the fly ash and in the deposits, and a more frequent shedding of the deposits was observed. The results imply that coal fly ash can be an effective additive to reduce ash deposition and corrosion problems in a pulverized wood...

The effect of the gas factor on selecting the thickness of a layer during two-layer getting of thick seams. [USSR

Energy Technology Data Exchange (ETDEWEB)

Varekha, Zh P; Kurkin, A S; Vechera, V N

1979-01-01

For technico-economic verification of the selection of the efficient removed thickness of upper and lower layers under conditions of high gas abundance of seams, the KNIUI has developed an economic model of converted costs within a getting field, allowing for natural and technical factors. The calculation considers specific costs for stoping work when getting the upper and lower layers, digging and maintenance of development workings, coal transport, assembly-disassembly work, ventilation, labor costs, degassing, etc. The calculation dependences and nomogram obtained enable comparatively easy definition of efficient thicknesses of removed layers when designing stoping work at thick, gently sloping seams, as well as calculation converted costs using as the initial data the total thickness of the seam, its natural gas content, and the expected degree of preliminary degassing.

Organic petrology and geochemistry of the Carboniferous coal seams from the Central Asturian Coal Basin (NW Spain)

Energy Technology Data Exchange (ETDEWEB)

Piedad-Sanchez, Noe; Martinez, Luis; Izart, Alain; Elie, Marcel [UMR G2R/7566, Geologie et Gestion des Ressources Minerales et Energetiques, Faculte des Sciences, Universite Henri Poincare, Nancy 1, BP-239, Boulevard des Aiguillettes, Vandoeuvre-les-Nancy Cedex 54506 (France); Suarez-Ruiz, Isabel [Instituto Nacional del Carbon (CSIC), C/ Francisco Pintado Fe, 26, Ap. Co., 73, Oviedo 33011 (Spain); Keravis, Didier [Institut des Sciences de la Terre (ISTO), CNRS-Universite d' Orleans, Batiment Geosciences, BP 6759, Orleans 45067 (France)

2004-03-23

This paper presents for the first time a petrological and geochemical study of coals from the Central Asturian Coal Basin (North Spain) of Carboniferous (Pennsylvanian), mainly of Moscovian, age. A paleoenvironmental approach was used, taking into account both petrographic and organic geochemical studies. Vitrinite reflectance (R{sub r}) ranges from 0.5% to 2.5%, which indicates a high volatile bituminous to semianthracite and anthracite coal rank. The coal samples selected for paleoenvironmental reconstruction are located inside the oil-gas-prone phase, corresponding to the interval between the onset of oil generation and first gas generation and efficient expulsion of oil. This phase is represented by coals that have retained their hydrocarbon potential and also preserved biomarker information. Paleodepositional reconstruction based on maceral and petrographic indices points to a swamp environment with vitrinite-rich coal facies and variable mineral matter content. The gelification index (GI) and groundwater influence index (GWI) indicate strong gelification and wet conditions. The biomarkers exhibit a high pristane/phytane ratio, suggesting an increase in this ratio from diagenetic processes, and a high diterpanes ratio. This, in turn, would seem to indicate a high swamp water table and a humid climate. The maximum point of coal accumulation occurred during the regressive part of the Late Moscovian sequence and in the most humid climate described for this period of time in the well-known coal basins of Europe and North America.

Evaluation of geological conditions for coalbed methane occurrence based on 3D seismic information: a case study in Fowa region, Xinjing coal mine, China

Science.gov (United States)

Li, Juanjuan; Li, Fanjia; Hu, Mingshun; Zhang, Wei; Pan, Dongming

2017-04-01

The research on geological conditions of coalbed methane (CBM) occurrence is of great significance for predicting the high abundance CBM rich region and gas outburst risk area pre-warning. The No. 3 coal seam, in Yangquan coalfield of Qinshui basin, is the research target studied by 3D seismic exploration technique. The geological factors which affect CBM occurrence are interpreted based on the 3D seismic information. First, the geological structure (faults, folds, and collapse columns) is found out by the 3D seismic structural interpretation and the information of buried depth and thickness of the coal seam is calculated by the seismic horizons. Second, 3D elastic impedance (EI) and natural gamma attribute volumes are generated by prestack EI inversion and multi-attribute probabilistic neural network (PNN) inversion techniques which reflect the information of coal structure types and lithology of the roof and floor. Then, the information of metamorphic degree of seam and hydrogeology conditions can be obtained by the geological data. Consequently, geological conditions of CBM occurrence in No. 3 coal seam are evaluated which will provide scientific reference for high abundance CBM rich region prediction and gas outburst risk area pre-warning.

A new experimental method to determine the CO2 sorption capacity of coal

NARCIS (Netherlands)

Hol, S.; Peach, C.J.; Spiers, C.J.

2010-01-01

Enhanced Coalbed Methane production (ECBM) involves the injection of CO2 to desorb CH4 from coal seams, and offers significant potential for deploying Carbon Capture and Storage (CCS). An essential starting parameter, determined in the laboratory, is the absolute CO2 storage potential of the coal

Assessment of 210Po deposition in moss species and soil around coal-fired power plant

International Nuclear Information System (INIS)

Nita Salina Abu Bakar; Ahmad Saat

2013-01-01

In the present study, the depositions of 210 Po were assessed in the surface soil and some mosses species found in the area around coal fired power plant using radiochemical deposition and alpha spectrometry counting system. The purposes of the study were to determine activity concentrations of 210 Po in mosses and surface soil collected around coal-fired power plant in relation to trace the potential source of 210 Po and to identify most suitable moss species as a bio-indicator for 210 Po deposition. In this study, different species of mosses, Orthodontium imfractum, Campylopus serratus and Leucobryum aduncum were collected in May 2011 at the area around 15 km radius from Tanjung Bin coal-fired power plant located in Pontian, Johor. The 210 Po activity concentrations in mosses and soil varied in the range 102 ± 4 to 174 ± 8 Bq/kg dry wt. and 37 ± 2 to 184 ± 8 Bq/kg dry wt., respectively. Corresponding highest activity concentration of 210 Po observed in L. aduncum, therefore, this finding can be concluded this species was the most suitable as a bio-indicator for 210 Po deposition. On the other hand, it is clear the accumulation of 210 Po in mosses might be supplied from various sources of atmospheric deposition such as coal-fired power plant operation, industrial, plantation, agriculture and fertilizer activities, burned fuel fossil and forest; and other potential sources. Meanwhile, the main source of 210 Po in surface soil is supplied from the in situ deposition of radon decay and its daughters in the soil itself. (author)

Coal waste management practices in the USA:an overview

Institute of Scientific and Technical Information of China (English)

Yoginder P. Chugh; Paul T. Behum

2014-01-01

This paper provides an overview of coal waste management practices with two case studies and an estimate of management cost in 2010 US dollars. Processing of as-mined coal typically results in considerable amount of coarse and fine coal processing wastes because of in-seam and out-of-seam dilution mining. Processing plant clean coal recovery values run typically 50%–80%. Trace metals and sulfur may be present in waste materials that may result in leachate water with corrosive charac-teristics. Water discharges may require special measures such as liner and collection systems, and treatment to neutralize acid drainage and/or water quality for trace elements. The potential for variations in coal waste production and quality depends upon mining or processing, plus the long-term methods of waste placement. The changes in waste generation rates and engineering properties of the coal waste during the life of the facility must be considered. Safe, economical and environmentally acceptable management of coal waste involves consideration of geology, soil and rock mechanics, hydrology, hydraulics, geochemistry, soil science, agronomy and environmental sciences. These support all aspects of the regulatory environment including the design and construction of earth and rock embankments and dams, as well as a wide variety of waste disposal structures. Development of impoundments is critical and require considerations of typical water-impounding dams and additional requirements of coal waste disposal impoundments. The primary purpose of a coal waste disposal facility is to dispose of unusable waste materials from mining. However, at some sites coal waste impoundments serve to provide water storage capacity for processing and flood attenuation.

Evaluation of ash deposits during experimental investigation of co-firing of Bosnian coal with wooden biomass

Energy Technology Data Exchange (ETDEWEB)

Smajevic, Izet; Kazagic, Anes [JP Elektroprivreda BiH d.d., Sarajevo (Bosnia and Herzegovina); Sarajevo Univ. (Bosnia and Herzegovina). Faculty of Mechanical Engineering

2008-07-01

The paper is addressed to the development and use different criteria for evaluation of ash deposits collected during experimental co-firing of Bosnian coals with wooden biomass. Spruce saw dust was used for the co-firing tests with the Kakanj brown coal and with a lignite blend consisted of the Dubrave lignite and the Sikulje lignite. The coal/biomass mixtures at 93:7 %w and at 80:20 %w were tested. Experimental lab-scale facility PF entrained flow reactor is used for the co-firing tests. The reactor allows examination of fouling/slagging behaviors and emissions at various and infinitely variable process temperature which can be set at will in the range from ambient to 1560 C. Ash deposits are collected on two non-cooled ceramic probes and one water-cooled metal surface. Six different criteria are developed and used to evaluate behavior of the ash deposits on the probes: ash deposit shape, state and structure, which are analyzed visually - photographically and optically by a microscope, rate of adhesion and ash deposit strength, analyzed by physic acting to the ash deposits, and finally deposition rate, determined as a mass of the deposit divided by the collecting area and the time of collecting. Furthermore, chemical composition analysis and AFT of the ash deposits were also done to provide additional information on the deposits. (orig.)

Evaluation of Rare Earth Element Extraction from North Dakota Coal-Related Feed Stocks

Science.gov (United States)

Laudal, Daniel A.

The rare earth elements consist of the lanthanide series of elements with atomic numbers from 57-71 and also include yttrium and scandium. Due to their unique properties, rare earth elements are crucial materials in an incredible array of consumer goods, energy system components and military defense applications. However, the global production and entire value chain for rare earth elements is dominated by China, with the U.S. currently 100% import reliant for these critical materials. Traditional mineral ores including previously mined deposits in the U.S., however, have several challenges. Chief among these is that the content of the most critical and valuable of the rare earths are deficient, making mining uneconomical. Further, the supply of these most critical rare earths is nearly 100% produced in China from a single resource that is only projected to last another 10 to 20 years. The U.S. currently considers the rare earths market an issue of national security. It is imperative that alternative domestic sources of rare earths be identified and methods developed to produce them. Recently, coal and coal byproducts have been identified as one of these promising alternative resources. This dissertation details a study on evaluation of the technical and economic feasibility of rare earth element recovery from North Dakota lignite coal and lignite-related feedstocks. There were four major goals of this study: i) identify lignite or lignite-related feedstocks with total rare earth element content above 300 parts per million, a threshold dictated by the agency who funded this research as the minimum for economic viability, ii) determine the geochemistry of the feedstocks and understand the forms and modes of occurrence of the rare earth elements, information necessary to inform the development of extraction and concentration methods, iii) identify processing methods to concentrate the rare earth elements from the feedstocks to a target of two weight percent, a value

Enhanced Coal Bed Methane Recovery and CO2 Sequestration in the Powder River Basin

Energy Technology Data Exchange (ETDEWEB)

Eric P. Robertson

2010-06-01

Unminable coal beds are potentially large storage reservoirs for the sequestration of anthropogenic CO2 and offer the benefit of enhanced methane production, which can offset some of the costs associated with CO2 sequestration. The objective of this report is to provide a final topical report on enhanced coal bed methane recovery and CO2 sequestration to the U.S. Department of Energy in fulfillment of a Big Sky Carbon Sequestration Partnership milestone. This report summarizes work done at Idaho National Laboratory in support of Phase II of the Big Sky Carbon Sequestration Partnership. Research that elucidates the interaction of CO2 and coal is discussed with work centering on the Powder River Basin of Wyoming and Montana. Sorption-induced strain, also referred to as coal swelling/shrinkage, was investigated. A new method of obtaining sorption-induced strain was developed that greatly decreases the time necessary for data collection and increases the reliability of the strain data. As coal permeability is a strong function of sorption-induced strain, common permeability models were used to fit measured permeability data, but were found inadequate. A new permeability model was developed that can be directly applied to coal permeability data obtained under laboratory stress conditions, which are different than field stress conditions. The coal permeability model can be used to obtain critical coal parameters that can be applied in field models. An economic feasibility study of CO2 sequestration in unminable coal seams in the Powder River Basin of Wyoming was done. Economic analyses of CO2 injection options are compared. Results show that injecting flue gas to recover methane from CBM fields is marginally economical; however, this method will not significantly contribute to the need to sequester large quantities of CO2. Separating CO2 from flue gas and injecting it into the unminable coal zones of the Powder River Basin seam is currently uneconomical, but can

Control over surrounding rocks deformation of soft floor and whole-coal gateways with trapezoidal supports

Energy Technology Data Exchange (ETDEWEB)

Zhai, X.; Li, D.; Shao, Q.; Sun, Y. [Henan Polytechnic University, Jaozuo (China). Dept. of Resource and Material Engineering

2005-06-01

The coal seams of Guengcun Coal mine of Yima Coal Group Co. Ltd. are prone to spontaneous combustion. Fully mechanized longwall mining with sublevel caving is used as the mining method. Based on the characteristics of the gateways of the 1301 coal face and of the roof coal seams, the natural equilibrium arch theory was used to design the parameters of 11 mine-type metal supports. Then, in-situ supporting experiments were carried out. The results indicate that under the action of virgin rock stress, the width of broken rocks zone of surrounding rocks is 1.7-2.0 m in the return heading and 1.1-1.3 m in the outgoing headway and their surrounding rocks belong to the IV-type soft rock and the III-type common surrounding rock respectively. Therefore, under the movable abutment pressure, the gateway deformation is serious. At the same time, the accumulated water on gateway floor must be drained in time. These measures were taken in the 1302 and 1304 coal faces in Gengcun colliery, and satisfactory results have been obtained. 8 refs., 3 figs.

FY 2000 survey of the geological structure overseas, etc. Japan-China joint coal exploration - Yu Xian project; 2000 nendo kaigai chishitsu kozo nado chosa - futai shiryoshu. Nippon Chugoku sekitan kyodo tansa Yu Xian project

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

This data book summarized the proceedings and the technical report of the management committee on the Japan-China geological structure survey based on the consultation concluded between NEDO and China's bureau of coal field geology and a report meeting on the Yu Xian project. In the exploration, conducted were the boring survey of 10 boreholes, seismic survey of 2D (71 traverse lines, 180.105km) and 3D (1.5km{sup 2}), VSP (6 holes (345 shots)) and the low velocity band survey (2,072 shots). The geological structure of the area presented the syncline structure with a gentle line associated with foldings and a number of faults and was classified into the medium class or the class of a little complication in the Chinese standard. The number of the faults confirmed in this exploration totaled 57. Coal reserves by coal seam were 157.22 million tons at No. 5 seam and 102.57 million tons at No. 1 seam. The total amount of the two seams was 79.1% of the total coal amount in all area. The coal quality of Nos. 1 and 5 was brown coal - flame coal in the Chinese classification, and subbituminous coal B - subbituminous coal C in the ASTM classification. The coal, however, cannot be used for process raw coal. There is a technical potentiality of the fixed bed pressurized gasification. (NEDO)

Combustion behaviour of Sydney and Bowen Basin coals determined by thermogravimetry

Energy Technology Data Exchange (ETDEWEB)

Benfell, K.E.; Beamish, B.B.; Rodgers, K.A.; Crosdale, P.J. [University of Auckland, Auckland (New Zealand). Department of Geology

1996-08-01

Assesses the suitability of thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis techniques to characterise the combustion behaviour of Sydney and Bowen basin coals. Results indicate that the thermogravimetric technique is suitable for characterising the effects of rank, maceral, sub-maceral and seam variations on the combustion behaviour of these coals. 6 refs., 6 figs., 2 tabs.

ENVIRONMENT PROTECTION THROUGH DETECTION OF HOT SPOTS USING THERMOGRAPHY IN COAL DEPOSITS BEFORE SELF IGNITION

Directory of Open Access Journals (Sweden)

Alina DINCĂ

2009-12-01

Full Text Available In this paper is presented a way to contribute to the environmental protection when it comes to coal which waits in big deposits to be burned for energy production. Because of certain parameters, in some places, the deposited coal could overheat and self ignite, thus loosing its caloric properties and even lead to fire. In this case the losses could be even higher, and the effect on the environment even worse. In order to prevent this self ignition to happen, an infrared camera can be mounted on a system, and the camera together with software which interprets the thermographic images, can alarm the personnel who is in charge with coal surveillance that the coal will ignite unless they take immediate measures. Also, there will be presented the limits we have found by now in the way of finalizing the application.

Equations describing contamination of run of mine coal with dirt in the Upper Silesian Coalfield

Energy Technology Data Exchange (ETDEWEB)

Winiewski, J J

1977-12-01

Statistical analysis proved that contamination with dirt of run of mine coal from seams in the series 200 to 600 of the Upper Silesian Coalfield depends on the average ash content of a given raw coal. A regression equation is deduced for coarse and fine sizes of each coal. These equations can be used to predict the degree of contamination of run of mine coal to an accuracy sufficient for coal preparation purposes.

Genetic stratigraphy and palaeoenvironmental controls on coal distribution in the Witbank Basin Coalfield

Energy Technology Data Exchange (ETDEWEB)

LeBlanc, G

1981-01-01

Subsurface data from over 1200 boreholes in the Witbank basin coalfield provided information for determining the coalfield stratigraphy and the palaeoenvironmental controls on coal distribution. The inadequacies of existing coalfield lithostratigraphy are obviated by the erection of a genetic coalfield stratigraphy. A total of ten areally extensive defined marker surfaces resolve the sedimentary succession into nine defined fundamental genetically realted stratal increments, termed Genetic increments of strata(GIS's); these are grouped into four defined Genetic Sequences of Strata (GSS's), termed from the base upwards, the Witbank, Coalville, Middleburg and Van Dyks Drift GSS's which are respectively grouped to comprise a single genetic Generation of strata, termed the Ogies Generation. Coalfield genetic stratigraphy is summarized in graphic mode in a composite stratigraphic column. It is concluded from this study that with the northward retreat of the late-Palaeozoic Gondwana ice sheet a series of glacial valleys, partially filled with diamicite, dominated the landscape along the northern edge of the Karoo basin. Consequent outwash sediments constitute the Witbank GSS and accumulated as paraglacial, glaciofluvial and glaciolacustrine deltaic deposits, in the primeval Dwyka-Ecca Sea. Upon abandonment, shallow-rooted Tundra vegetation proliferated, and multi-channel outwash streams were stabilised, confined and enveloped by areally extensive accumulation of peat, that reached up to 24 m in thickness, and which constituted precursors to the 1 and 2 Seam coals which attain a combined thickness of up to 12,5 m. Variations i coal petrographic character and ash content are attributed to: overbank splaying within the proximity of recognisable syndepositional (in-seam) vegetation-stabilised channels; and to the progressively increased introduction of suspended sediment as a consequence of transgressive inundation prior to burial.

Underground gasification of coal. [Newman Spinney

Energy Technology Data Exchange (ETDEWEB)

1950-06-16

This article gives an account of the experimental work on underground gasification at Newman Spinney near Sheffield, England. An attempt was made to develop the percolation technique in flat coal seams but to demonstrate first that gas can be made underground. A borehole system was created on an opencast site where an exposed seam face would allow horizontal drilling to be carried out. Details of trails are given, and drilling techniques, electromagnetic device developed by the Great Britain Post Office Research Branch and radioactive location developed by the Anglo-Iranian Oil Company. An account is given of the inauguration of a series of experiments on May 22, 1950.

Probabilistic assessment of the impact of coal seam gas development on groundwater: Surat Basin, Australia

Science.gov (United States)

Cui, Tao; Moore, Catherine; Raiber, Matthias

2018-05-01

Modelling cumulative impacts of basin-scale coal seam gas (CSG) extraction is challenging due to the long time frames and spatial extent over which impacts occur combined with the need to consider local-scale processes. The computational burden of such models limits the ability to undertake calibration and sensitivity and uncertainty analyses. A framework is presented that integrates recently developed methods and tools to address the computational burdens of an assessment of drawdown impacts associated with rapid CSG development in the Surat Basin, Australia. The null space Monte Carlo method combined with singular value decomposition (SVD)-assisted regularisation was used to analyse the uncertainty of simulated drawdown impacts. The study also describes how the computational burden of assessing local-scale impacts was mitigated by adopting a novel combination of a nested modelling framework which incorporated a model emulator of drawdown in dual-phase flow conditions, and a methodology for representing local faulting. This combination provides a mechanism to support more reliable estimates of regional CSG-related drawdown predictions. The study indicates that uncertainties associated with boundary conditions are reduced significantly when expressing differences between scenarios. The results are analysed and distilled to enable the easy identification of areas where the simulated maximum drawdown impacts could exceed trigger points associated with legislative `make good' requirements; trigger points require that either an adjustment in the development scheme or other measures are implemented to remediate the impact. This report contributes to the currently small body of work that describes modelling and uncertainty analyses of CSG extraction impacts on groundwater.

Preliminary reservoir model of enhanced coalbed methane (ECBM) in a subbituminous coal seam, Huntly Coalfield, New Zealand

Energy Technology Data Exchange (ETDEWEB)

Zarrouk, Sadiq J. [Department of Engineering Science, University of Auckland, Private Bag 92019, Auckland (New Zealand); Moore, Tim A. [Solid Energy New Zealand Ltd, PO Box. 1303, Christchurch (New Zealand)]|[Department of Geological Sciences, University of Canterbury, Christchurch (New Zealand)

2009-01-07

The Huntly coalfield has significant coal deposits that contain biogenically-sourced methane. The coals are subbituminous in rank and Eocene in age and have been previously characterised with relatively low to moderate measured gas (CH{sub 4}) contents (2-4 m{sup 3}/ton). The CO{sub 2} holding capacity is relatively high (18.0 m{sup 3}/ton) compared with that of CH{sub 4} (2.6 m{sup 3}/ton) and N{sub 2} (0.7 m{sup 3}/ton) at the same pressure (4 MPa; all as received basis). The geothermal gradient is also quite high at 55 C/km. A study has been conducted which simulates enhancement of methane recovery (ECBM) from these deposits using a new version of the TOUGH2 (version 2) reservoir simulator (ECBM-TOUGH2) that can handle non-isothermal, multi-phase flows of mixtures of water, CH{sub 4}, CO{sub 2} and N{sub 2}. The initial phase of the simulation is CH{sub 4} production for the first 5 years of the field history. The model indicates that methane production can be significantly improved (from less than 80% recovery to nearly 90%) through injection of CO{sub 2}. However, although an increase in the rate of CO{sub 2} injection increases the amount of CO{sub 2} sequestered, the methane recovery (because of earlier breakthrough with increasing injection rate) decreases. Modeling of pure N{sub 2} injection produced little enhanced CH{sub 4} production. The injection of a hypothetical flue gas mixture (CO{sub 2} and N{sub 2}) also produced little increase in CH{sub 4} production. This is related to the low adsorption capacity of the Huntly coal to N{sub 2} which results in almost instantaneous breakthrough into the production well. (author)

Consultancy in the development of coal deposits all over the world

Energy Technology Data Exchange (ETDEWEB)

Gold, R.; Schiebel, W.

1977-04-01

Dr. Otto Gold, Consulting Engineers, Cologne, are working as consultants in the area of prospecting, exploration and development of lignite deposits. Some projects successfully carried out are reported on, being an example for other consulting projects on the coal sector.

Relationship between weathered coal deposits and the etiology of Balkan endemic nephropathy

International Nuclear Information System (INIS)

Feder, G.L.; Radovanovic, Z.; Finkelman, R.B.

1991-01-01

Field studies in epidemiology and environmental geochemistry in areas in Yugoslavia containing villages with a high incidence of Balkan endemic nephropathy (BEN), indicate a possible relationship between the presence of low-rank coal deposits and the etiology of BEN. Preliminary results from qualitative chemical analyses of drinking water from shallow farm wells indicate the presence of soluble polar aromatic and polynuclear aromatic hydrocarbons. These compounds may be derived from weathering of low-rank coals occurring in the vicinity of the endemic villages. All of the endemic villages are in alluvial valleys of tributaries to the Danube River. All except one of the clusters of endemic villages are located in the vicinity of known Pliocene age coals. Detailed sampling of the drinking waters and the nearby coals are being undertaken to identify a possible etiologic factor

Determination of combustible volatile matter in coal mine roadway dusts by backscatter of x-rays from a radioisotope source

International Nuclear Information System (INIS)

Ailwood, C.R.; Bunch, K.; Fookes, R.A.; Gravitis, V.L.; Watt, J.S.

1977-01-01

The combustible volatile matter in coal mine roadway dusts (CVM) has been determined using x-ray backscatter techniques. The correlation between x-ray and chemical techniques is reasonably good for the 92 samples from collieries on the Bulli seam, and the maximum error expected at the maximum level of 11.5 weight per cent CVM permitted in the N.S.W. Coal Mines Regulation Act, 1912, as amended, is about +- 2.5 weight per cent. This x-ray technique can be used only when the combustible volatile content of the coal matter (CVM) varies within a limited range, and a separate calibration is required for each coal seam. Portable equipment based on a radioisotope x-ray source and digital ratemeter makes possible simple and rapid analysis, and with adaptation to use in coal mines should lead to much more comprehensive testing of roadways and hence improved overall prevention of coal dust explosions. (author)

78 FR 48461 - Notice of Competitive Coal Lease Sale, WYW172684, Wyoming

Science.gov (United States)

2013-08-08

... Basin. The tract will be leased to the qualified bidder of the highest cash amount provided that the high bid meets or exceeds the BLM's estimate of the fair market value (FMV) of the tract. The minimum... seams or splits containing less than 5 feet of coal. The total mineable stripping ratio of the coal in...

Research on comprehensive gas permeability improvement technology by hydraulic fracturing and slotting in coal seam with complex geological conditions and low permeability%复杂地质低渗煤层水力压裂-割缝综合瓦斯增透技术研究

Institute of Scientific and Technical Information of China (English)

贾同千; 饶孜; 何庆兵; 宋润权; 白鑫

2017-01-01

Aiming at the problem of gas drainage in the coal seam with complex geological conditions and low permeability in Baijiao Coal Mine,the hydraulic fracturing technology was applied to carry out the regional gas permeability improvement,and its application effect was analyzed according to the situation of field gas drainage.Aiming at the blind area of regional gas permeability improvement by hydraulic fracturing,the technical measure of localized gas permeability improvement by hydraulic slotting was put forward,then the comprehensive gas permeability improvement technology by hydraulic fracturing and slotting in coal seam with complex geological conditions and low permeability was formed,and the field verification was conducted.The results showed that the average pure flow rate of gas drainage for three fracturing boreholes in the hydraulic fracturing zone increased by 15.8 times than that of regular single borehole gas drainage in 238 floor laneway,and the gas drainage concentration increased by 4％.The pure flow rate of gas drainage in the fractured area increased by 2.1 times than that of the comparison zone,but there existed the blind area by the regional measures of hydraulic fracturing due to the restriction of geological conditions such as fault and coal seam hardness.The gas concentration of drainage borehole in the hydraulic slotting permeability improvement zone increased by 4.9 times on the average,and the pure flow rate of gas increased by 3.3 times on the average.It has strong adaptability to different geological conditions,but the influence range of slotting is small,and the drainage time is short.The comprehensive gas permeability improvement technology by hydraulic fracturing and slotting in coal seam with complex geological conditions and low permeability integrates the advantages of hydraulic fracturing and slotting,and it has strong adaptability to coal seam with complex geological conditions,which improves the gas control level greatly.The field

Cost of mining Eastern coal

International Nuclear Information System (INIS)

Anon.

1990-01-01

This paper, Chapter 7.2.3 of the 'surface mining' reference book, gives an example of how the cost of mining a ton of coal is calculated. Conditions set down are for a coal tract of 50.6 ha in West Virginia, USA to be mined by the contour surface method, the seam being 101.6cm thick. Elements of the costing are: permitting and bonding costs, engineering and construction costs, equipment and other operating expenses (such as hauling and wheeling), royalties, direct taxes and fees, costs of revegetation, and employment costs (payroll and medical expenses). 5 tabs

Coal graders in Czechoslovakian mines

Energy Technology Data Exchange (ETDEWEB)

Vasek, J.; Klimek, M.

1980-01-01

Problems related to sections of the area of application of graders depending on different mining and geological mining-engineering factors are examined. The principal factors are selected from a general group of influencing factors: dip angle of a formation, separability (shear ability) of coal, characteristics of country rocks, adhesion of coal to rock, tectonic fracturing of a seam, and thickness of a formation. Based on practical and theoretical studies all of the principal factors have been categorized. This allows one to obtain an objective picture of the possibility of using graders under specific conditions by comparing different factors.

The effect of petrographical composition of coals and bituminous sediments on the material and isotopic composition of dry natural gases from artificial recoalification reactions. 2

International Nuclear Information System (INIS)

Maass, I.; Huebner, H.; Nitzsche, H.-M.; Schuetze, H.; Zschiesche, M.

1975-01-01

Experimental results indicate that on the basis of the material and isotopic composition of natural gases conclusions can be drawn with regard to the character (humic or bituminous) of the parent rock. Thus, genetic relations assumed to exist between humic sediments (e.g. coal seams) and dry natural gases as well as bituminous rocks and wet natural gases are experimentally confirmed. In addition, from analyses of the materials approximate data can be derived on the degree of carbonization of coal or bituminous sediments in the main phase of gas separation. Furthermore, these analyses were used to elucidate the question whether authochthonous or allochthonous deposits are present. It could be shown that the maceral composition of coals and of the organo-petrographical inclusions in bituminous sediments determines the isotopic composition of methane in recoalification gases to a considerable degree. (author)

Successful coal winning with two shearers using chainless haulage

Energy Technology Data Exchange (ETDEWEB)

Fritz, W

1977-10-06

Coal winning in one production district at Rheinpreussen Colliery is described. Extracted seam thickness is 2.95 m, of which 1.15 m is dirt. Eickhoff double-ended ranging shearer loaders with Eicotrack chainless haulage have proved successful, even though this coal is difficult to cut because of the dirt bands. The introduction of twin-belt conveyor drives allowed the distances between centers in the long-haul belt systems to be increased, thereby improving safety.

Key technology for treating slack coal blockage in CBM recovery: A case study from multi-lateral horizontal wells in the Qinshui Basin

Directory of Open Access Journals (Sweden)

Yong Yang

2016-01-01

Full Text Available Due to the nature of coal bed, slack coal production is inevitable in gas recovery sby water drainage. When coalbed methane (CBM wells are reentered after low energy exploitation and shut-in, the negative effect of slack coal production on productivity of CBM is irreversible. In this paper, the CBM occurrence characteristics and multi-lateral horizontal well trajectory in the Qinshui Basin, Shanxi Province, were analyzed. In the multi-lateral horizontal wells, the expected gas production rate could not be reached and the production rate after shut-in maintenance could not restore to the level before shut-in. The reason for these issues is that migration pathways in the reservoirs are blocked by slack coal deposits, while formation water and slack coal deposit accumulated at the troughs of horizontal sections enlarge the resistance for gas to flow into the bottom hole. Furthermore, three key technologies to deal with slack coal blockage were proposed. Firstly, CBM horizontal well trajectory should follow the principle of keeping the wellbores smooth and updip instead of being “wavy”, on the premise of guaranteeing CBM drilling rate. Secondly, the cavities of production wells, as an important part of multi-lateral horizontal wells, are capable of settling sand, and can be used for gas–liquid–solid separation. And thirdly, a tree-like horizontal well with its main hole set on stable seam top or floor, provides a stable well flushing passage for coal powder. This research provides a useful attempt in solving the problem of slack coal production in gas recovery by water drainage.

Mineralogical investigations into ash deposits of selected brown coals; Mineralogische Untersuchungen an Ascheansaetzen ausgewaehlter Braunkohlen

Energy Technology Data Exchange (ETDEWEB)

Szilagyi, J.; Ullrich, B. [Technische Univ. Dresden, Inst. fuer Geotechnik (Germany)

2003-07-01

Within the framework of the research project financed by the Arbeitsgemeinschaft industrieller Forschungsvereinigungen (AIF) ''Experimental investigations into the formation of ash deposits from stack gases during the combustion of pulverised lignite'' and supervised by the chair of power station technology (Institute of Energy Technology) of the Dresden Technical University, the mineral composition of ash deposits of six different coals were investigated: two coal blends (different countries worldwide), two lignites from east from the River Elbe (types WM and JAe), one from west of the River Elbe and one Rhenish lignite. (orig.)

An overview of the geological controls in underground coal gasification

Science.gov (United States)

Mohanty, Debadutta

2017-07-01

Coal’s reign will extend well into this millennium as the global demand for coal is expected to increase on average by 2-1% per year through 2019. Enhanced utilization of the domestic coal resource through clean coal technologies is necessary to meet the energy needs while achieving reduced emissions. Underground coal gasification (UCG) is one of such potential technologies. Geology of the area plays decisive role throughout the life of a UCG project and imperative for every phase of the project cycle starting from planning, site selection, design to cessation of operations and restoration of the site. Impermeable over/underlying strata with low porosity and less deformation are most suitable for UCG processes as they act as seal between the coal seam and the surrounding aquifers while limiting the degree of subsidence. Inrush of excess water into the gasification chamber reduces the efficacy of the process and may even quench the reactions in progress. Presence of fresh water aquifer in the vicinity of target coal seam should be abandoned in order to avoid groundwater contamination. UCG is not a proven technology that is still evolving and there are risks that need to be monitored and managed. Effective shutdown programme should intend at minimising the post-burn contaminant generation by flushing out potential organic and inorganic contaminants from the underground strata and treating contaminants, and to restore ground water quality to near baseline conditions.

Aluminized film, seam sealing tests and observations. Final report

Energy Technology Data Exchange (ETDEWEB)

1994-06-16

The purpose of this work was to investigate various seam sealing techniques, reinforcing methods, fitting installations, seam tolerances and geometric configurations pertinent to an aluminized plastic laminate. The program seeks a successful fabricating method for producing low-diffusion, cylindrical, spar liners to contain pressurized GH{sub 2} and GO{sub 2}. The test plan included: (1) seaming techniques on metallized Mylar film; (2) ``double patches`` for end fittings; (3) stainless steel bulkhead fitting assembly with seals; (4) minimum run tolerance on linear shear seam; (5) peel seam vs. inverted seal seam fabrication.

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�

Briquetability of coal fines from the Lavci deposit near Resen. Briketabilnost sitnih frakcija uglja sa lezista Lavci kod Resena

Energy Technology Data Exchange (ETDEWEB)

Jankuloska, V.; Cadikovska, V. (Rudnici i Zelezarnica, Skopje (Yugoslavia))

1990-01-01

Describes laboratory briquetting of lignite from the Lavci coal deposit in Macedonia, Yugoslavia. The deposit has 21.4 Mt of lignite reserves. Coal samples from cores of exploratory boreholes were evaluated. Chemical composition and properties of the coal are presented. The coal has a 60.8% moisture, 7.8% ash and 0.82% sulfur content. The calorific value of coal is between 5,881 and 7,828 kJ/kg. Coal samples were comminuted and briquetted without binders, due to the favorable petrographic composition of the lignite. Resulting laboratory briquets weighing 45 g were tested for compression strength, water resistance and abrasion (Micum test). Briquet combustion properties were also determined. Briquet quality was of Yugoslav class B[sub 1] and B[sub 2] with the lowest calorific value being 16,427 kJ/kg, which is 2.79 times higher than that of the raw coal. 3 refs.

Environmental impact assessment for steeply dipping coal beds: North Knobs site

Energy Technology Data Exchange (ETDEWEB)

1978-11-08

The US Department of Energy is funding an underground coal gasification (UCG) project in steeply dipping coal beds (SDB), at North Knobs, about 8 miles west of Rawlins, Carbon County, Wyoming. The project is being conducted to determine the technical, economic and environmental viability of such a technology. The development of SDB is an interesting target for UCG since such beds contain coals not normally mineable economically by ordinary techniques. Although the underground gasification of SDB has not been attempted in the US, Soviet experience and theoretical work indicate that the gasification of SDB in place offers all the advantages of underground gasification of horizontal coal seams plus some unique characteristics. The steep angle of dip helps to channel the produced gases up dip to offtake holes and permits the ash and rubble to fall away from the reaction zone helping to mitigate the blocking of the reaction zone in swelling coals. The intersection of SDB with the surface makes the seam accessible for drilling and other preparation. The tests at the North Knobs site will consist of three tests, lasting 20, 80 and 80 days, respectively. A total of 9590 tons of coal is expected to be gasified, with surface facilities utilizing 15 acres of the total section of land. The environmental effects of the experiment are expected to be very small. The key environmental impact is potential groundwater contamination by reaction products from coal gasification. There is good evidence that the surrounding coal effectively blocks the migration of these contaminants.

Cooling Effect Analysis of Suppressing Coal Spontaneous Ignition with Heat Pipe

Science.gov (United States)

Zhang, Yaping; Zhang, Shuanwei; Wang, Jianguo; Hao, Gaihong

2018-05-01

Suppression of spontaneous ignition of coal stockpiles was an important issue for safe utilization of coal. The large thermal energy from coal spontaneous ignition can be viewed as the latent energy source to further utilize for saving energy purpose. Heat pipe was the more promising way to diffuse effectively concentrated energy of the coal stockpile, so that retarding coal spontaneous combustion was therefore highly desirable. The cooling mechanism of the coal with heat pipe was pursued. Based on the research result, the thermal energy can be transported from the coal seam to the surface continuously with the use of heat pipe. Once installed the heat pipes will work automatically as long as the coal oxidation reaction was happened. The experiment was indicated that it can significantly spread the high temperature of the coal pile.

Microstructures and microtextures of natural cokes: A case study of heat-affected coking coals from the Jharia coalfield, India

Energy Technology Data Exchange (ETDEWEB)

Singh, Ashok K. [Central Fuel Research Institute, CSIR, Dhanbad-828108 (India); Singh, Mahendra P. [Department of Geology, Banaras Hindu University, Varanasi-221005 (India); Sharma, Mamta; Srivastava, Sunil K.

2007-07-02

In Jharia coalfield, nearly 1250 Mt of coking coal has been devolatilized due to igneous intrusives and {proportional_to} 1900 Mt due to mine fires. This paper is an effort to investigate the effect of carbonization in two intrusive affected coal seams of Ena (seam XIII) and Alkusa (seam XIV) collieries of this coalfield. Through petrographic studies by microscopy, characterization of normal and heat-affected coals was carried out. The microstructures and microtextures produced due to extraneous heat have been related to nature and extent of heat, location of heating source, and quality and quantity of natural coke produced. Based on the results of this study and earlier studies, an effort has been made to study the classification scheme for microtextures of natural cokes generated through in-situ carbonization of the coal seams. It has been observed that in case of such heat effects under overburden pressure, the anisotropy is much more pronounced as compared to laboratory-carbonized cokes. In the mildly carbonized coals (pre-plastic phase, < 300 C) the vitrinite attained higher reflectance than normal vitrinite, liptinite started disappearing, and inertinite remained unaffected. In the moderately affected coals (plastic phase, 300-500 C), mesophase spheres and fused natural cokes were generated from the reactives (vitrinite and liptinite maceral groups), the liptinites disappeared, and structurally, the inertinites remained almost unchanged with slight increase in the reflectance value. In the severely heat-affected coals (post plastic phase, > 500 C) the identified microtextures were mesophase spheres, different shapes and sizes of natural cokes, graphitic sphaeroliths, pyrolytic carbons, inerts with morpho-structural changes and slightly higher reflectance values, and altered and unaltered mineral matters. A gradual change in the heat-affected coals with increasing temperature was observed with respect to location of intrusive body. It has been concluded that

Development and linearization of generalized material balance equation for coal bed methane reservoirs

International Nuclear Information System (INIS)

Penuela, G; Ordonez R, A; Bejarano, A

1998-01-01

A generalized material balance equation was presented at the Escuela de Petroleos de la Universidad Industrial de Santander for coal seam gas reservoirs based on Walsh's method, who worked in an analogous approach for oil and gas conventional reservoirs (Walsh, 1995). Our equation was based on twelve similar assumptions itemized by Walsh for his generalized expression for conventional reservoirs it was started from the same volume balance consideration and was finally reorganized like Walsh (1994) did. Because it is not expressed in terms of traditional (P/Z) plots, as proposed by King (1990), it allows to perform a lot of quantitative and qualitative analyses. It was also demonstrated that the existent equations are only particular cases of the generalized expression evaluated under certain restrictions. This equation is applicable to coal seam gas reservoirs in saturated, equilibrium and under saturated conditions, and to any type of coal beds without restriction on especial values of the constant diffusion

Development of science and technology in underground coal mining in Czechoslovakia during the 7th 5 year plan

Energy Technology Data Exchange (ETDEWEB)

Klimek, M.

1982-01-01

Reviews main tasks of underground coal mining in Czechoslovakia from 1981 to 1985 in the following basins: Ostrava-Karvina, Kladno, Prievidza, Most and Sokolov. The planned increase of brown and black coal output in each of the basins is discussed. Selected problems associated with mining are evaluated: significant increase of mining depth, rock burst hazards, methane hazards and water influx in the Ostrava-Karvina basin. Investment program in the current 5 year plan as well as until the year 2000 is analyzed: sinking of 38.8 km of mine shafts and 4.4 km of blind shafts. Equipment for shaft sinking produced in the USA (by Robins the 241 SB-184) and in the USSR (the Uralmash Sk-1U system) is compared. Design and technical specifications of the two systems are given. Equipment for mine drivage is also reviewed. The following machines are described: the TVM-55H by Demag (FRG), the TBS V-600E/Sch by Wirth (FRG), the TBM ser. 18a781 by Robins (USA) and the MARK-18T by JARVA (USA). Selected types of powered supports which will be widely used in coal mines in the current 5 year plan are evaluated. Research programs in underground coal mining are reviewed (safety, mining thin coal seams, slice mining of thick coal seams in the Namurian B series, mining extremely thick seams with stowing of the top slice and mining with caving the 4.5 m thick bottom slice). (4 refs.) (In Czech)

Molecular and elemental analyses of the carbonaceous matter in the gold and uranium bearing Vaal Reef carbon seams, Witwatersrand sequence

International Nuclear Information System (INIS)

Zumberge, J.E.; Sigleo, A.C.; Nagy, B.

1978-01-01

The thin Vaal Reef carbon seams consist of a complex, solid, and solvent insoluble, polymer-like substance, containing mainly hydrocarbons and some organic sulphur and oxygen compounds. These carbon seams are not pure carbon, e.g. graphite, and do not contain only hydrocarbons. According to modern terminology the Vaal Reef carbonaceous matter is most appropriately referred to as kerogen rather than carbon or thucholite. This kerogen is not the result of the polymerization of gaseous or liquid hydrocarbons, but rather of the polymerization of biochemicals from decayed, primitive Precambrian micro-organisms. These microbiota formed mats in which uranium minerals and gold became incorporated before burial under younger sediments. Organic geochemistry was first developed as a means to elucidate the nature and composition of petroleum and coal. Later it was successfully used in lunar sample, planetary surface, and meteorite studies as well as in investigations of kerogens in terrestrial sediments of various ages. Considering economic geology, organic geochemistry holds promise for elucidating the origin and helping in the exploration of carbonaceous ore deposits. The purpose of this report is to review some of the major current organic geochemical methods and to illustrate these by the analysis of the Vaal Reef kerogen. The samples were analysed by a directly connected high vacuum pyrolysis system-gas chromatograph-organic mass spectrometer. Additional analyses were performed by a combined scanning electron microscope-electron microprobe, by the techniques of electron paramagnetic resonance spectroscopy, and by neutron activation analysis

Enhanced coal bed methane production and sequestration of CO₂ in unmineable coal

Energy Technology Data Exchange (ETDEWEB)

Locke, James [CONSOL Energy Inc., South Park, PA (United States); Winschel, Richard [CONSOL Energy Inc., South Park, PA (United States)

2005-03-01

The Marshall County Project was undertaken by CONSOL Energy Inc. (CONSOL) with partial funding from the U. S. Department of Energy’s (DOE) Carbon Storage Program (CSP). The project, initiated in October 2001, was conducted to evaluate opportunities for carbon dioxide CO2 sequestration in an unmineable coal seam in the Northern Appalachian Basin with simultaneous enhanced coal bed methane recovery. This report details the final results from the project that established a pilot test in Marshall County, West Virginia, USA, where a series of coal bed methane (CBM) production wells were developed in an unmineable coal seam (Upper Freeport (UF)) and the overlying mineable Pittsburgh (PIT) seam. The initial wells were drilled beginning in 2003, using slant-hole drilling procedures with a single production leg, in a down-dip orientation that provided limited success. Improved well design, implemented in the remaining wells, allowed for greater CBM production. The nearly-square-shaped project area was bounded by the perimeter production wells in the UF and PIT seams encompassing an area of 206 acres. Two CBM wells were drilled into the UF at the center of the project site, and these were later converted to serve as CO2 injection wells through which, 20,000 short tons of CO2 were planned to be injected at a maximum rate of 27 tons per day. A CO2 injection system comprised of a 50-ton liquid CO2 storage tank, a cryogenic pump, and vaporization system was installed in the center of the site and, after obtaining a Class II underground injection permit (UIC) permit from the West Virginia Department of Environmental Protection (WVDEP), CO2 injection, through the two center wells, into the UF was initiated in September 2009. Numerous complications limited CO2 injection continuity, but CO2 was injected until breakthrough was encountered in September 2013, at which point the project had achieved an injection total of 4,968 tons of CO2. During the injection and post

Effect of Seams on Drape of Fabrics | Sukumar | African Research ...

African Journals Online (AJOL)

In this study drape of ten fabrics are analyzed with three types of seams and three stitch densities. Sample without seam is a control sample and drape of seamed samples are compared with control sample to analyse the drape behavior of seamed fabrics. This paper presents a fundamental drape analysis of seamed fabrics ...

Geological control in computer-based resource estimation

International Nuclear Information System (INIS)

Cram, A.A.

1992-01-01

The economic assessment of mineral deposits potentially involves a number of phases from initial assessment through to detailed orebody evaluation and subsequently to estimation of bench or stope grades in an operational mine. Obviously the nature and quantity of information varies significantly from one extreme to the other. This paper reports on geological interpretation which obviously plays a major part during the early phases of assessment and it logically follows that computerized orebody assessment techniques must be able to effectively utilize this information. Even in an operational mine the importance of geological control varies according to the type of orebody. The method of modelling coal seams is distinctly different from those techniques used for a massive sulphide deposit. For coal seams significant reliance is placed on the correlation of seam intercepts from holes which are widely spaced in relation to the seam (i.e.) orebody) thickness. The use of geological interpretation in this case is justified other experience gained in the past, compared to the cost of reliance only on samples from a very dense drill hole pattern

Full-scale ash deposition measurements at Avedøre Power Plant unit 2 during suspension-firing of wood with and without coal ash addition

DEFF Research Database (Denmark)

Wu, Hao; Shafique Bashir, Muhammad; Jensen, Peter Arendt

The formation of deposits during suspension-firing of wood at Avedøre Power Plant unit 2 (AVV2) was studied by using an advanced deposit probe system. The tests were conducted both with and without coal ash addition, and at two different locations with flue gas temperatures of 1250-1300 oC and 750...... with a high flue gas temperature of 1250-1300 oC, although the addition of coal fly ash increased the differential deposit formation rate (DDF-rate) and the ash deposition propensity, the deposit removal frequency were considerably increased and the major shedding mechanism was changed from soot...... corrosion. At the location with a low flue gas temperature of 750-800 oC, the addition of coal fly ash reduced the ash deposition propensity and caused the formed deposits being easily removable. Moreover, the KCl and KOH/K2CO3 found in the low-temperature deposits without coal ash addition disappeared when...

Investigation of the feasibility of underground coal gasification in North Dakota, United States

International Nuclear Information System (INIS)

Pei, Peng; Nasah, Junior; Solc, Jaroslav; Korom, Scott F.; Laudal, Daniel; Barse, Kirtipal

2016-01-01

Highlights: • A four-year feasibility study of underground coal gasification is presented. • A test site was selected for feasibility investigation. • Gasification test, a hydrogeological study and geomechanical study were performed. • Results suggest favorable conditions for UCG development at the selected site. - Abstract: Underground coal gasification (UCG) is a promising technology that has the potential to recover currently-unmineable coal resources. The technical feasibility and economic success of a UCG project is highly site specific. Any risks associated with UCG, such as subsidence, groundwater contamination, and syngas quality, should be sufficiently evaluated through a feasibility study. This paper presents a four-year UCG feasibility study utilizing lignite seams in North Dakota, United States. Four wells were drilled through the lignite seams at a selected site, and lignite and strata cores were recovered. A geological model of the formation was built, coal and rock properties were analyzed, and field hydrogeological tests and laboratory gasification tests were performed. This work provided valuable insights in rock mechanics, hydrogeology, and coal properties. The study results show that the selected site is suitable for development of a UCG plant because there are minimal induced subsidence risks, there is hydrological isolation from major aquifers and the coal produces desirable syngas quality for liquid fuel production. Methodologies developed in this study will benefit the design, optimization and management of the UCG process.

Underground coal gasification: An overview of groundwater contamination hazards and mitigation strategies

Energy Technology Data Exchange (ETDEWEB)

Camp, David W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); White, Joshua A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-03-13

Underground coal gasification is the in situ conversion of coal into an energy-rich product gas. It takes place deep underground, using chemical reactions to consume the coal and grow a cavity. Gas wells, drilled into the coal seam, inject reactant air, oxygen, and/or steam to sustain the reactions. Production wells then extract the product gas. Careful analysis and understanding of likely failure modes will help prevent and minimize impacts. This document provides a general description of the relevant processes, potential failure modes, and practical mitigation strategies. It can guide critical review of project design and operations.

49 CFR 230.30 - Lap-joint seam boilers.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Lap-joint seam boilers. 230.30 Section 230.30..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Inspection and Repair § 230.30 Lap-joint seam boilers. Every boiler having lap-joint longitudinal seams...

The nexus of the coal industry and the state in Australia: Historical dimensions and contemporary challenges

International Nuclear Information System (INIS)

Baer, Hans A.

2016-01-01

This article presents a historical account of the close relationship between the coal mining industry and the federal and various state governments, thus over time building a state/coal industry nexus in Australia. It examines (1) an early colonial stage extending from the late 18th century to around the time of Federation in 1902 when the nexus emerged; (2) an intermediate stage from the early 20th century to the late 1970s when the nexus became solidified; and (3) a late stage from the early 1980s to the present day when the corporate sector came to dominate the nexus. Both Coalition and Australian Labor Party governments have consistently supported the exploitation of Australia's coal and natural gas, including recently coal seam gas, and supported the expansion of coal ports. An opposition movement has called for leaving coal and coal seam gas in the ground and shifting Australia’s energy production to renewable sources, particularly solar and wind energy. The article highlights how the nexus between coal mining and the state inhibits action on climate change. It argues this can be transcended by energy policy directed at socializing coal mining, wedded to a program of transitioning it to renewable energy production. - Highlights: • A close nexus exists between the coal industry and the state in Australia. • An anti-coal movement has developed in recent years in Australia. • Breaking the coal industry/state nexus requires socialization of energy production. • This would enable a shift from reliance on coal to renewable energy sources.

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.

The coal cleat system: A new approach to its study

OpenAIRE

C.F. Rodrigues; C. Laiginhas; M. Fernandes; M.J. Lemos de Sousa; M.A.P. Dinis

2014-01-01

After a general analysis regarding the concept of coal “cleat system”, its genetic origin and practical applications to coalbed methane (CBM) commercial production and to CO2 geological sequestration projects, the authors have developed a method to answer, quickly and accurately in accordance with the industrial practice and needs, the following yet unanswered questions: (1) how to define the spatial orientation of the different classes of cleats presented in a coal seam and (2) how to determ...

Effect of fuel type and deposition surface temperature on the growth and structure of ash deposit collected during co-firing of coal with sewage-sludge, saw-dust and refuse derived fuel

Energy Technology Data Exchange (ETDEWEB)

Kupka, Tomasz; Zajac, Krzysztof; Weber, Roman [Clausthal Univ. of Technology, Clausthal-Zellerfeld (Germany). Inst. of Energy Process Engineering and Fuel Technology

2008-07-01

Blends of a South African bituminous ''Middleburg'' coal and three alternative fuels (a municipal sewage-sludge, a saw-dust and a refuse derived fuel) have been fired in the slagging reactor to examine the effect of the added fuel on slagging propensity of the mixtures. Two kinds of deposition probes have been used, un-cooled ceramic probes and air-cooled steal probes. Distinct differences in physical and chemical structures of the deposits collected using the un-cooled ceramic probes and air-cooled metal probes have been observed. Glassy, easily molten deposits collected on un-cooled ceramic deposition probes were characteristic for co-firing of municipal sewage-sludge with coal. Porous, sintered (not molten) but easily removable deposits of the same fuel blend have been collected on the air-cooled metal deposition probes. Loose, easy removable deposits have been sampled on air-cooled metal deposition probe during co-firing of coal/saw-dust blends. The mass of the deposit sampled at lower surface temperatures (550-700 C) was always larger than the mass sampled at higher temperatures (1100-1300 C) since the higher temperature ash agglomerated and sintered much faster than the low temperature deposit. (orig.)

Chemometric Study of Trace Elements in Hard Coals of the Upper Silesian Coal Basin, Poland

Science.gov (United States)

Rompalski, Przemysław; Cybulski, Krzysztof; Chećko, Jarosław

2014-01-01

The objective of the study was the analysis of trace elements contents in coals of the Upper Silesian Coal Basin (USCB), which may pose a potential threat to the environment when emitted from coal processing systems. Productive carbon overburden in central and southern zones of the USCB is composed mostly of insulating tertiary formations of a thickness from a few m to 1,100 m, and is represented by Miocene and Pliocene formations. In the data study the geological conditions of the coal seams of particular zones of the USCB were taken into account and the hierarchical clustering analysis was applied, which enabled the exploration of the dissimilarities between coal samples of various zones of the USCB in terms of basic physical and chemical parameters and trace elements contents. Coals of the northern and eastern zones of the USCB are characterized by high average Hg and low average Ba, Cr, and Ni contents, whereas coals of southern and western zones are unique due to high average concentrations of Ba, Co, Cu, Ni, and V. Coals of the central part of the USCB are characterized by the highest average concentration of Mn and the lowest average concentrations of As, Cd, Pb, V, and Zn. PMID:24967424

Distribution and sedimentary arrangement of carbon in South African proterozoic placer deposits

International Nuclear Information System (INIS)

Minter, W.E.L.

1981-01-01

Carbon, which occurs as grains, films, and thin seams in Witwatersrand Proterozoic placer deposits, is generally confined to carbon-seam reefs that were deposited in distal environments. The distribution of carbon on paleosurfaces, on sedimentary accumulation surfaces like pebble layers, on trough-shaped bedforms of pi-crossbedded units and foresets, and on the winnowed top of placer sediments implies that its growth took place contemporaneously with placer deposition in an aquatic fluvial environment. The areal distribution of carbon seams in distal environments is patchy, and its sparsity or total absence in some areas does not affect either the gold or the uranium content of the placer. High gold and uranium contents that appear to be associated with carbon seams are at the base of the reef because that position represents both the stable consolidated paleosurface upon which the plant material anchored itself and also the surface of bedload concentration

Solid-Gas Coupling Model for Coal-Rock Mass Deformation and Pressure Relief Gas Flow in Protection Layer Mining

OpenAIRE

Zhu, Zhuohui; Feng, Tao; Yuan, Zhigang; Xie, Donghai; Chen, Wei

2018-01-01

The solid-gas coupling model for mining coal-rock mass deformation and pressure relief gas flow in protection layer mining is the key to determine deformation of coal-rock mass and migration law of pressure relief gas of protection layer mining in outburst coal seams. Based on the physical coupling process between coal-rock mass deformation and pressure-relief gas migration, the coupling variable of mining coal-rock mass, a part of governing equations of gas seepage field and deformation fiel...

Analysis of gas migration patterns in fractured coal rocks under actual mining conditions

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