With the identification of coal deposits that are enriched in rare earth elements(REEs)across the world,coal and coal by-products are considered as an alternative source for REEs due to the combined supply and demand ...With the identification of coal deposits that are enriched in rare earth elements(REEs)across the world,coal and coal by-products are considered as an alternative source for REEs due to the combined supply and demand restrictions for these elements.Studies are being conducted to recover these elements from various coal sources.In this study,coal samples from the East Kootenay coalfields in British Columbia,Canada were examined for the presence of REEs in run-of-mine coal samples and flotation products.Results reveal that on an ash basis,the concentration of REEs varies from 174 to 1038 mg/kg in the samples.To understand the REE as sociation,which is essential for extraction purposes,a three-step sequential extraction process along with a mineralogical evaluation using scanning electron microscopy(SEM)with energy dispersive X-ray spectroscopy(EDX)and quantitative X-ray diffraction(XRD)data was used.It is found that a significant portion of REEs in the feed samples were reported to middling and tailings streams.The mineralogical analyses reveal REE association with aluminosilicate mineral in the samples.展开更多
This study investigates the paleodepositional conditions of the No.6 Seam of the Madzaringwe Formation in Makhado and Voorburg south area of the Soutpansberg Coalfield(Limpopo Province,South Africa)utilizing organic p...This study investigates the paleodepositional conditions of the No.6 Seam of the Madzaringwe Formation in Makhado and Voorburg south area of the Soutpansberg Coalfield(Limpopo Province,South Africa)utilizing organic petrography and inorganic geochemical proxies.The coals are predominantly high-volatile bituminous B-A rank with high ash yields(avg.36.1 wt%),characterized by high-vitrinite(~41.5 vol%),moderate-to-high inertinite(9.8 vol%–33.7 vol%)and low liptinite(~2.3 vol%).The distribution of inertinite varies among different coal horizons(from bottom-lower to middle-upper),suggesting differential oxidation conditions and/or paleofire occurrence.Vitrinite-to-inertinite(V/I)ratio,tissue preservation–gelification index(TPI–GI),and groundwater–vegetation index(GWI–VI)plots,indicate that the peat-forming forest-swamp vegetation accumulated under mesotrophic-to-rheotrophic hydrological conditions.The presence of structured macerals(i.e.,telinite,collotelinite,fusinite,and semifusinite)suggests well-preserved plant tissues,whereas framboidal pyrite and sulphur content(0.24 wt%–2.16 wt%)point to brackish-water influence at the peat stage.The coals contain quartz,kaolinite,siderite,muscovite,dolomite,calcite,and pyrite minerals,most of which were likely sourced from felsic igneous rocks.The Al/(Al+Fe+Mn)and(Fe+Mn)/Ti ratios for the studied samples range between 0.24–0.97 and 0.57–70.10,respectively.The ratios,Al–Fe–Mn plot,and presence of massive botryoidal-type pyrite imply some influence of meteoric waters or fluids from hydrothermal activity post-deposition.Moreover,the chemical index of alteration(CIA:98.25–99.67),chemical index of weathering(CIW:92.04–97.66),and A–CN–K ternary diagram suggest inorganic matter suffered strong chemical weathering,indicating warm paleoclimatic conditions during the coal formation.展开更多
3D geological modeling is an inevitable choice for coal exploration to adapt to the transformation of coal mining for green, fine, transparent and Intelligent mining. In the traditional Coalfield exploration geologica...3D geological modeling is an inevitable choice for coal exploration to adapt to the transformation of coal mining for green, fine, transparent and Intelligent mining. In the traditional Coalfield exploration geological reports, the spatial expression form for the coal seams and their surrounding rocks are 2D maps. These 2D maps are excellent data sources for constructing 3D geological models of coal field exploration areas. How to construct 3D models from these 2D maps has been studying in coal exploration industry for a long time, and still no breakthrough has been achieved so far. This paper discusses the principle, method and software design idea of constructing 3D geological model of an exploration area with 2D maps made by AutoCAD/MapGIS. At first, the paper analyzes 3D geological surface expression mode in 3D geological modeling software. It is pointed out that although contour method has unique advantages in coal field exploration, TIN (Triangular Irregular Network) is still the standard configuration of 3D modeling software for coal field. Then, the paper discusses the method of 2D line features obtaining elevation and upgrading 2D curve to 3D curve. Next, the method of semi-automatic partition is introduced to build the boundary ring of the surface patch, that is, the user clicks and selects the line feature to build the outer boundary ring of the surface patch. Then, Auto-process method for fault line inside of the outer boundary ring is discussed, it including construction of fault ring, determining fault ring being normal fault ring or reverse fault ring and an algorithm of dealing with normal fault ring. An algorithm of dealing with reverse fault ring is discussed detailly, the method of expanding reverse fault ring and dividing the duplicate area in reverse fault into two portions is introduced. The paper also discusses the method of extraction ridge line/valley line, the construction of fault plane, the construction of stratum and coal body. The above ideas and methods have been initially implemented in the “3D modeling platform for coal field exploration” software, and applied to the 3D modeling practice of data from several coal field exploration areas in Ningxia, Shanxi, Qinghai, etc.展开更多
Coal oxidation at low temperatures is the heat source liable for the self-heating and spontaneous combustion of coal. This phenomenon has imposed severe problems in coal related industries. Attempts to understand this...Coal oxidation at low temperatures is the heat source liable for the self-heating and spontaneous combustion of coal. This phenomenon has imposed severe problems in coal related industries. Attempts to understand this phenomenon by previous researchers have provided significant progress. It is wellknown that coal oxidation at low temperatures involves oxygen consumption and formation of gaseous and solid oxidation products. This process is majorly influenced by temperature, oxidation history of coal,coal properties, particle size distribution of the coal, etc. The current understanding of the phenomenon of self-heating and spontaneous combustion of coal is discussed along with the different experimental and numerical models established to predict self-heating characteristics of coal. This paper focuses on the global position of the study carried out by academics, research institutes and industries on spontaneous combustion of coal and coal mine fires. Within this framework, the generally used spontaneous combustion techniques to predict the spontaneous combustion liability of coal were evaluated. These techniques are well-known in their usage, but no specific method has become a standard to predict the spontaneous combustion liability. Further study is still needed to indicate a number of impending issues and to obtain a more complete understanding on the phenomenon.展开更多
This study presents a review of the various methods to predict the spontaneous combustion liability of coal and coal-shale. The relative propensity of coal to undergo self-heating can be established by different metho...This study presents a review of the various methods to predict the spontaneous combustion liability of coal and coal-shale. The relative propensity of coal to undergo self-heating can be established by different methods. These methods are well established in their usage, but the fact that no particular test method has become a standard to predict the spontaneous combustion liability indicates that doubt still exists as to the validity of all of them. The underlying principle of all the tests is that the more readily the coal undergoes exothermic oxidation, the more liable it is to self-heat. Comprehensive studies that centres on the international position on research being conducted by academics, different research institutes and industries on spontaneous combustion of coal and coal mine fires were evaluated. Relationships between the geochemical analysis (proximate and ultimate analysis, forms of sulphur, petrographic properties, X-ray diffraction and X-ray fluorescence) and spontaneous combustion testing methods (numerical and experimental approaches) used to predict the spontaneous combustion liability of coal were reviewed. The combination of these tests provides a better understanding of the mechanism that controls the spontaneous combustion phenomena. However, irrespective of the extensive studies that have been conducted over time, spontaneous combustion is still a major problem in the coal value chain.展开更多
Total 138 coal samples and 14 parting samples were taken from the No. 6 Seam of the Jungar Coalfield, Inner Mongolia. These samples were analysed by optical microscopy, sequential chemical extraction procedure (SCEP...Total 138 coal samples and 14 parting samples were taken from the No. 6 Seam of the Jungar Coalfield, Inner Mongolia. These samples were analysed by optical microscopy, sequential chemical extraction procedure (SCEP), inductively coupled plasma mass spectrometry (ICP-MS), X-ray powder diffraction (XRD), and scanning electron microscope in conjunction with an energy-dispersive X-ray spectrometer (SEM-EDX) analysis. The results indicate that the Li contents have reached the industrial grade of the coal associated Li deposit, and the total Li reserves have reached 2406600 tons, that is, 5157000 tons Li2O in the No. 6 seam in the Jungar Coalfield. The sequential chemical extraction procedure results suggest that the Li concentration is mainly related to inorganic matter. The minerals in the coals consist of kaolinite, boehmite, chlorite-group mineral, quartz, calcite, pyrite, siderite and amorphous clay material. Some Li could be absorbed by clay minerals in the Li-bearing coal seam. The chlorite phase?could be?most likely the host for a part of Li. The Yinshan Oldland should be the most possible source of Li of the coal.展开更多
This paper discussed the petrographic characteristics of No.6 coal from the Xiaoyugou mine,Jungar Coalfield,Ordos Basin,China.10 samples(7 coal,1 parting mudstone and 2 floor mudstone)were analysed by microscopical an...This paper discussed the petrographic characteristics of No.6 coal from the Xiaoyugou mine,Jungar Coalfield,Ordos Basin,China.10 samples(7 coal,1 parting mudstone and 2 floor mudstone)were analysed by microscopical and geochemical methods.Four maceral compositions and several associated elements parameters were selected as indicators and corresponding diagrams were drawn to explicate the sedimentary environment.The results indicate that the maceral is dominated by vitrinite and minerals are mainly kaolinite in the No.6 coal.The sedimentary facies vary from barrier island system to tidal-flat which is a deposition process of water body shallowing and the coal-forming plants are herbs and woody plants formed in swamps.展开更多
Total of 23 bench samples were taken from the No. 7 Coal of Iqe Coalfield, Qinghai Province, China, following Chinese Standard Method GB/T 482-2008 (2008). These samples were analyzed by powder X-ray diffraction (...Total of 23 bench samples were taken from the No. 7 Coal of Iqe Coalfield, Qinghai Province, China, following Chinese Standard Method GB/T 482-2008 (2008). These samples were analyzed by powder X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP- MS) and X-ray fluorescence (XRF). The results indicate that the No. 7 Coal belongs to a low rank (Ro.ran =0.659%) and high-ash coal (40.54%). Compared to common Chinese and world low-rank coals, the lqe coal contains anomalous concentrations of rare metal elements, rare-scattered (dispersed) elements and rare earth elements. The highest contents of Rb, Cs, Ga and REY reach to 180, 26, 37, and 397 ppm, respectively. Their average contents of these elements are 10.9, 15, 4.8 and 3.5 times higher than those of world coals, respectively. Minerals in the coal include kaolinite, quartz, muscovite, siderite, and traces of rutile, and brookite. Kaolinite could be main host minerals of Rb, Cs, Ga and REY. The anomalous rare element Rb and Cs accumulation in the Iqe coal is related to both organic and inorganic matter. The REY concentrations may be related to circulation of thermal solutions, contained or sorbed by clayey particles, and organic matter as well.展开更多
Santanghu Coalfield is the largest integrated coalfield exploration area in China. The major coal seams developing in Xishanyao Formation (Middle Jurassic) are the high-quality steam coals characterized by large thick...Santanghu Coalfield is the largest integrated coalfield exploration area in China. The major coal seams developing in Xishanyao Formation (Middle Jurassic) are the high-quality steam coals characterized by large thickness, favorable horizontal continuity and high coal quality. In this paper, twenty-two samples were collected from the three typical boreholes in Hanshuiquan disirict, representing the 11 coal seam sequences (7#,8#,9#,13#, 14#,15#,17#,18#,19#,20#,22#), respectively. The petrographic characteristics of the coal-bearing sequence in Xishanyao Formation were firstly summarized systematicly, and then the coal-forming swamp characteristics and succession mechanism of the coal seam in Xishanyao Formation were defined by analyzing the samples. The maceral composition, structure, geochemical and geophysical characteristics of coal are in eluded in original genetic criteria of coal-forming swamp an alysis. And the composition of coal petrography, maceral and microlithotype are the most frequently used parameters. Coal is composed of microscopic constituents and inorganic substances. The Xishanyao Formation maceral mainly consists of vitrinite (65.74%-97.01 %), inert i nite (1.93%-34%), and the exinite shows the mode of regular change. The coal-forming swamp in Xishanyao Formation possesses the characteristics of mainly marsh, wet forest swamp facies, and shallow water covered forest swamp facies, and a few of coal seams distribute in the deep water covered forest swamp facies. In addition, the sporopollens in Xishanyao Formation are mainly Pinaceae evergreen broad leaf and needle-leaved plants. Osmundaceae, Cyatheaceae and Lygodiaceae, indicating that the warm and humid tropic-subtropical climate conductive to the persistent growth of coal-forming plants in the Middle Jurassic. The coal-forming swamp shows the characteristics of vertically upward fluctuation through the periodic transition. It indicates a shallow-deep-shallow change process of the water covered depth in the swamp. This is the prin ci pal factor for the formation of the high-quality and continuous coal seam in Hanshuiquan district, Santanghu Coalfield.展开更多
Coal and coal-shale undergo low-temperature oxidation when exposed to air,potentially leading to spontaneous combustion.Coal-shale found in association with coal seams vary considerably in their intrinsic properties a...Coal and coal-shale undergo low-temperature oxidation when exposed to air,potentially leading to spontaneous combustion.Coal-shale found in association with coal seams vary considerably in their intrinsic properties and spontaneous combustion liability index.Fourteen coal-shale samples collected from four different coal mines in Witbank Coalfield,South Africa,were experimentally investigated.The influence of coal-shale intrinsic properties and spontaneous combustion liability indices(determined by the WitsEhac Index and the Wits-CT Index)were established.The liability indices indicate relationships with the intrinsic factors and thus,identifying the major intrinsic factors affecting liability toward spontaneous combustion in these coal-shale samples.The XRF analysis indicated that the coal-shale samples are rich in Si O2,Al2O3 and Fe2O3,while the XRD showed that same coal-shale samples are generally dominated with kaolinite and quartz.The coal-shale occurred in association with medium Rank C bituminous coal and contained varying proportion of macerals.The Wits-Ehac Index was unable to reliably determine liability indices of some coal-shale samples,and hence the Wits-CT Index was developed.The results obtained from the characterisation tests may be used as a tool to predict the spontaneous combustion liability in carbonaceous material and may serve as a reference when comparing coal-shale from different coal mines.展开更多
Based on the systematic analysis of the coal gangue in Weibei Coalfield, such as petrologic characteristics, chemical composition, nutrient elements, deleterious elements, and the transformation, and compared with the...Based on the systematic analysis of the coal gangue in Weibei Coalfield, such as petrologic characteristics, chemical composition, nutrient elements, deleterious elements, and the transformation, and compared with the soil element content background values of Loess Plateau and national harmful materials controlling standards, we conclude that the coal gangue in the Weibei Coalfield has huge potential to be used as clay fertilizer.展开更多
In this paper,the spatio-temporal variation and propagation direction of coal fire were studied in the Jharia Coalfield(JCF),India during 2006–2015 through satellite-based night-time land surface temperature(LST)imag...In this paper,the spatio-temporal variation and propagation direction of coal fire were studied in the Jharia Coalfield(JCF),India during 2006–2015 through satellite-based night-time land surface temperature(LST)imaging.The LST was retrieved from Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)night-time thermal-infrared data by a robust split-window algorithm based on scene-specific regression coefficients,band-specific hybrid emissivity,and night-time atmospheric transmittance.The LST-profile-based coal fire detection algorithm was formulated through statistical analysis of the LST values along multiple transects across diverse coal fire locations in the JCF in order to compute date-specific threshold temperatures for separating thermally-anomalous and background pixels.This algorithm efficiently separates surface fire,subsurface fire,and thermally-anomalous transitional pixels.During the observation period,it was noticed that the coal fire area increased significantly,which resulted from new coal fire at many places owing to extensive opencast-mining operations.It was observed that the fire propagation occurred primarily along the dip direction of the coal seams.At places,lateral-propagation of limited spatial extent was also observed along the strike direction possibly due to spatial continuity of the coal seams along strike.Moreover,the opencast-mining activities carried out during 2009–2015 and the structurally weak planes facilitated the fire propagation.展开更多
Coal spontaneous combustion(CSC)is a disaster associated with coal mining that leads to loss of coal resources and envi-ronmental and human health issues.To investigate kinetic characteristics for oxidation of coal,th...Coal spontaneous combustion(CSC)is a disaster associated with coal mining that leads to loss of coal resources and envi-ronmental and human health issues.To investigate kinetic characteristics for oxidation of coal,three coal samples were collected from different coal mining areas in the Southern Junggar coalfield.Subsequently,the collected coal samples were ground into different particle sizes and tested using microscopic and macroscopic methods,including thermal gravimetric analysis,Fourier transform infrared spectroscopy,X-ray diffraction,and temperature-programmed oxidation.The results obtained are as follows:the sharpest absorption peak(002)indicates that graphitization is high.Furthermore,the results show that the SKS coal sample is prone to spontaneous combustion;the greater the aromatic hydrocarbon content is,the more difficult it is for CSC to occur,while the opposite is true for oxygen-containing functional groups.The SKS data confirmed this conclusion;the rate for generation of CO and CO_(2)controlled the possibility of SKS oxidation at 110℃and provided an indication of the temperature.During the dehydration stage,the WD sample had the lowest activation energy,indicating that it was most susceptible to spontaneous combustion.During the combustion stage,the lowest activation energy was found for the SKS sample with particle sizes<0.075 mm,indicating that particle size was one of the factors affecting spontane-ous combustion.The activation energy for dehydration was significantly lower than that for combustion,which showed that the coal oxygen reaction was more likely to occur in the dehydration stage.Based on DSC curves,the SKS sample had the largest exothermicity,indicating that it would ignite more readily.展开更多
Heavy mining of Jurassic and Carboniferous horizontal coal seams in the Datong coalfield has seriously affected the local geological environment, which is mainly manifested by such geohazards as soil avalanches, lands...Heavy mining of Jurassic and Carboniferous horizontal coal seams in the Datong coalfield has seriously affected the local geological environment, which is mainly manifested by such geohazards as soil avalanches, landslides, mudflows, surface subsidence, surface cracks, surface solid waste accumulation and surface deformation. More seriously, coal mining causes groundwater to leak. Overpumping of groundwater has resulted in substantial land subsidence of the urban area in Datong City. Based on the previous geo-environmental investigation in the work area, the authors used radar remote sensing techniques such as InSAR (synthetic aperture radar interferometry) and D-InSAR (differential synthetic aperture radar interferometry), supplemented by the optical remote sensing method, for geo-environmental investigation to ascertain the geo-environmental background of the Datong Jurassic and Carboniferous-Permian coalfield and evaluate the effects of the geohazards, thus providing a basis for the geo-environmental protection, geohazard control and prevention, land improvement and optimization of the human environment. In this study 8 cog-nominal ERS-1/2 SAR data frames during 1992 to 2003 were used, but the following processing was made: (1) the multitemporal SAR magnitude images were used to interpret the geological structure, vegetation, microgeomorphology and drainage system; (2) the multi-temporal InSAR coherent images were used to make a classification of surface features and evaluate the coherence change due to coal mining; and (3) the multi-temporal cog-nominal SAR images were used to complete D-InSAR processing to remove the information of differential deformation areas (sites). In the end, a ten-year time series of differential interferograms were obtained using the multi-temporal cog-nominal SAR images. In the tests, 84 deformed areas (sites) were obtained, belonging to those in 1993-1996, 1996-1997, 1997-1998, 1998-2001, 1998-2002 and 2001-2003 respectively. Of the 84 areas, 44 are mining subsidence ones, 23 urban subsidence ones and 17 landslide subsidence ones. They cover a total area of 1824.4 km^2, equivalent to the area of the whole Datong coalfield. Then an accurate evaluation was made on the geo-environment of the Datong coalfield. The tests show that InSAR is now the only feasible technical means for making one all-weather, real-time measurement of a coal mining land subsidence area covering up to 10,000 km^2 to subcentimeter resolution. This study is a successful application of InSAR in the investigation and evaluation of land subsidence, especially in coal mining areas.展开更多
The occurrence of coal-bearing strata in a variety of coal-bearing basins of China is characterized by late tectonic deformation and remarkable spatial and geochronologic differences.The main controlling factors,which...The occurrence of coal-bearing strata in a variety of coal-bearing basins of China is characterized by late tectonic deformation and remarkable spatial and geochronologic differences.The main controlling factors,which determine the tectonic framework of coalfields,include the geodynamic environment,tectonic evolution,deep structures,tectonic stress,and lithologic combination of the coal measures.The Chinese continent has experienced multi-stage tectonic movements since the Late Paleozoic.The spatial and temporal heterogeneity of its continental tectonic evolution,the complexity of its basement properties,and its stratigraphic configurations control the tectonic framework of its coalfields’present complex and orderly patterns.The concept of coal occurrence structural units is proposed in this paper and is defined as the structural zoning of coal occurrence.China’s coalfields are divided into five coal occurrence structural areas,and the structural characteristics of the coalfields in five main coal occurrence areas throughout the country are summarized.Based on the analysis of the relationship between the structure characteristics and occurrence of coal in these coalfields,the coal-controlling structures are divided into six groups:extensional structural styles,compressional structural styles,shearing and rotational structural styles,inverted structural styles,sliding structural styles,and syn-depositional structural styles.In addition,the distribution of coal-controlling structural styles is briefly summarized in this paper.展开更多
Based on analysis of a large data set and supplementary sampling and analysis for hazardous trace elements in coal samples from the Huainan Coalfield,a generalized contrast-weighted scale index method was used to esta...Based on analysis of a large data set and supplementary sampling and analysis for hazardous trace elements in coal samples from the Huainan Coalfield,a generalized contrast-weighted scale index method was used to establish a model to evaluate the grade of coal cleanliness and its regional distribution in the main coal seam(No.13-1)The results showed that:(1)The contents of Cr,Mn and Ni in the coal seam are relatively high and the average values are greater than 20μg/g.The contents of Se and Hg are at a high level while most other trace elements are at normal levels.(2)The cleanliness grade of the coal seam is mainly grade III-IV,which corresponds to a relatively good-medium coal cleanliness grade.However,some parts of the seam are at grade V(relatively poor coal cleanliness).(3)Coal of relatively good cleanliness grade(grade III)is distributed mainly in the regions corresponding to the Zhuji-Dingji-Gubei coal mines and in the eastern periphery of the Panji coal mine.Coal of medium cleanliness(grade IV)is distributed mainly in the regions of the Panji-Xiejiaji and Kouzidong coalmines.Relatively poor grade coal(grade V)is distributed in the southwest regions of the coalfield and the contents of Cr,As and Hg in coal collected from the relatively poor coal cleanliness regions often exceed the regulatory standards for the maximum concentration limits.展开更多
The history of coalfield geology and mine geology IT applications is over 30 years,which is gaining remarkable achievements.This paper sheds light on the development of geological and surveying spatial management info...The history of coalfield geology and mine geology IT applications is over 30 years,which is gaining remarkable achievements.This paper sheds light on the development of geological and surveying spatial management information systems.Specifically,this study proposed the development trend,system structure and function design and sub-systems of the new generation of geological and surveying spatial management information system by benefitting from the recent advancements in computer and spatial information technologies.The sub-systems include the“One Map”online collaborative(2D-GIS)management platform,the geological survey mapping collaborative management system,the integrated service system based on“one map”,the three-dimensional dynamic geological model system,the three-dimensional transparent management platform,and water prevention and control information management system.This work is an important foundation to realize the IT information and intelligent management of coal industry.The successful development and application of the new generation of geological and surveying spatial management information system will provide the dynamic data support for the online decision-making of the intelligent coal mining.展开更多
Igneous intrusion into coal-bearing strata can cause an abrupt increase of temperature-pressure and trigger hydrothermal circulation at the igneous rock-coal contact zone. The conductive heat of intruded lnagma and co...Igneous intrusion into coal-bearing strata can cause an abrupt increase of temperature-pressure and trigger hydrothermal circulation at the igneous rock-coal contact zone. The conductive heat of intruded lnagma and convective migration of secondary hydrothermal fluids have been observed to significantly alter the concentrations and modes of occurrence of mercury (Hg) in thermally-intruded coals.展开更多
Adsorption isotherm relates the gas storage capacity as a function of pressure at constant temperature.In this paper,adsorption isotherm of two dry borehole samples was constructed in the laboratory using the manometr...Adsorption isotherm relates the gas storage capacity as a function of pressure at constant temperature.In this paper,adsorption isotherm of two dry borehole samples was constructed in the laboratory using the manometric method.Isotherm was measured for two gases,i.e.,CH4 and CO2 to pressure up to 8.4 MPa.Before the construction of sorption isotherm,coal was characterized by proximate,ultimate and petrographic analysis.Coalbed gas content of these two samples was found 2.29 m3/t and 2.75 m3/t.SEM images were obtained for the pore size distribution of coal using pore image analysis.Prediction of coalbed methane recovery from CH4 adsorption isotherm showed that these coalbeds are under saturated.CO2 isotherm was constructed to estimate enhanced coalbed methane(ECBM)recovery.Volume wise CO2/CH4 sorption ratio was found 2.09 times to 2.75 times respectively.This paper presents the interpretation of isotherm data to find the recovery factor of methane production from Jharia coalfield.展开更多
Shale oil occurs in free state (including condensate state), adsorption state (adsorbed on kerogen and mineral particles) and dissolved state (dissolved in natural gas, residual water, etc.) in shales and adjace...Shale oil occurs in free state (including condensate state), adsorption state (adsorbed on kerogen and mineral particles) and dissolved state (dissolved in natural gas, residual water, etc.) in shales and adjacent layers. The characterization of the occurrence of different hydrocarbons in shale oil, especially the quantitative separation of free hydrocarbons (mobile oil), has been the current focus of shale oil research. Taken the shale oil from the Muli coalfield in Qilian Mountain as an example, this work extracted shale samples with organic solvents of different polarity to obtain different occurrence states of hydrocarbons in the oil-bearing shale and to reveal the compositional differences of the hydrocarbons. The result may provide new geochemical information for the occurrence and mobility of shale oil.展开更多
文摘With the identification of coal deposits that are enriched in rare earth elements(REEs)across the world,coal and coal by-products are considered as an alternative source for REEs due to the combined supply and demand restrictions for these elements.Studies are being conducted to recover these elements from various coal sources.In this study,coal samples from the East Kootenay coalfields in British Columbia,Canada were examined for the presence of REEs in run-of-mine coal samples and flotation products.Results reveal that on an ash basis,the concentration of REEs varies from 174 to 1038 mg/kg in the samples.To understand the REE as sociation,which is essential for extraction purposes,a three-step sequential extraction process along with a mineralogical evaluation using scanning electron microscopy(SEM)with energy dispersive X-ray spectroscopy(EDX)and quantitative X-ray diffraction(XRD)data was used.It is found that a significant portion of REEs in the feed samples were reported to middling and tailings streams.The mineralogical analyses reveal REE association with aluminosilicate mineral in the samples.
文摘This study investigates the paleodepositional conditions of the No.6 Seam of the Madzaringwe Formation in Makhado and Voorburg south area of the Soutpansberg Coalfield(Limpopo Province,South Africa)utilizing organic petrography and inorganic geochemical proxies.The coals are predominantly high-volatile bituminous B-A rank with high ash yields(avg.36.1 wt%),characterized by high-vitrinite(~41.5 vol%),moderate-to-high inertinite(9.8 vol%–33.7 vol%)and low liptinite(~2.3 vol%).The distribution of inertinite varies among different coal horizons(from bottom-lower to middle-upper),suggesting differential oxidation conditions and/or paleofire occurrence.Vitrinite-to-inertinite(V/I)ratio,tissue preservation–gelification index(TPI–GI),and groundwater–vegetation index(GWI–VI)plots,indicate that the peat-forming forest-swamp vegetation accumulated under mesotrophic-to-rheotrophic hydrological conditions.The presence of structured macerals(i.e.,telinite,collotelinite,fusinite,and semifusinite)suggests well-preserved plant tissues,whereas framboidal pyrite and sulphur content(0.24 wt%–2.16 wt%)point to brackish-water influence at the peat stage.The coals contain quartz,kaolinite,siderite,muscovite,dolomite,calcite,and pyrite minerals,most of which were likely sourced from felsic igneous rocks.The Al/(Al+Fe+Mn)and(Fe+Mn)/Ti ratios for the studied samples range between 0.24–0.97 and 0.57–70.10,respectively.The ratios,Al–Fe–Mn plot,and presence of massive botryoidal-type pyrite imply some influence of meteoric waters or fluids from hydrothermal activity post-deposition.Moreover,the chemical index of alteration(CIA:98.25–99.67),chemical index of weathering(CIW:92.04–97.66),and A–CN–K ternary diagram suggest inorganic matter suffered strong chemical weathering,indicating warm paleoclimatic conditions during the coal formation.
文摘3D geological modeling is an inevitable choice for coal exploration to adapt to the transformation of coal mining for green, fine, transparent and Intelligent mining. In the traditional Coalfield exploration geological reports, the spatial expression form for the coal seams and their surrounding rocks are 2D maps. These 2D maps are excellent data sources for constructing 3D geological models of coal field exploration areas. How to construct 3D models from these 2D maps has been studying in coal exploration industry for a long time, and still no breakthrough has been achieved so far. This paper discusses the principle, method and software design idea of constructing 3D geological model of an exploration area with 2D maps made by AutoCAD/MapGIS. At first, the paper analyzes 3D geological surface expression mode in 3D geological modeling software. It is pointed out that although contour method has unique advantages in coal field exploration, TIN (Triangular Irregular Network) is still the standard configuration of 3D modeling software for coal field. Then, the paper discusses the method of 2D line features obtaining elevation and upgrading 2D curve to 3D curve. Next, the method of semi-automatic partition is introduced to build the boundary ring of the surface patch, that is, the user clicks and selects the line feature to build the outer boundary ring of the surface patch. Then, Auto-process method for fault line inside of the outer boundary ring is discussed, it including construction of fault ring, determining fault ring being normal fault ring or reverse fault ring and an algorithm of dealing with normal fault ring. An algorithm of dealing with reverse fault ring is discussed detailly, the method of expanding reverse fault ring and dividing the duplicate area in reverse fault into two portions is introduced. The paper also discusses the method of extraction ridge line/valley line, the construction of fault plane, the construction of stratum and coal body. The above ideas and methods have been initially implemented in the “3D modeling platform for coal field exploration” software, and applied to the 3D modeling practice of data from several coal field exploration areas in Ningxia, Shanxi, Qinghai, etc.
基金The work presented in this paper is part of a PhD research study in the School of Mining Engineering at the University of the Witwatersrand,Johannesburg,South Africa.
文摘Coal oxidation at low temperatures is the heat source liable for the self-heating and spontaneous combustion of coal. This phenomenon has imposed severe problems in coal related industries. Attempts to understand this phenomenon by previous researchers have provided significant progress. It is wellknown that coal oxidation at low temperatures involves oxygen consumption and formation of gaseous and solid oxidation products. This process is majorly influenced by temperature, oxidation history of coal,coal properties, particle size distribution of the coal, etc. The current understanding of the phenomenon of self-heating and spontaneous combustion of coal is discussed along with the different experimental and numerical models established to predict self-heating characteristics of coal. This paper focuses on the global position of the study carried out by academics, research institutes and industries on spontaneous combustion of coal and coal mine fires. Within this framework, the generally used spontaneous combustion techniques to predict the spontaneous combustion liability of coal were evaluated. These techniques are well-known in their usage, but no specific method has become a standard to predict the spontaneous combustion liability. Further study is still needed to indicate a number of impending issues and to obtain a more complete understanding on the phenomenon.
文摘This study presents a review of the various methods to predict the spontaneous combustion liability of coal and coal-shale. The relative propensity of coal to undergo self-heating can be established by different methods. These methods are well established in their usage, but the fact that no particular test method has become a standard to predict the spontaneous combustion liability indicates that doubt still exists as to the validity of all of them. The underlying principle of all the tests is that the more readily the coal undergoes exothermic oxidation, the more liable it is to self-heat. Comprehensive studies that centres on the international position on research being conducted by academics, different research institutes and industries on spontaneous combustion of coal and coal mine fires were evaluated. Relationships between the geochemical analysis (proximate and ultimate analysis, forms of sulphur, petrographic properties, X-ray diffraction and X-ray fluorescence) and spontaneous combustion testing methods (numerical and experimental approaches) used to predict the spontaneous combustion liability of coal were reviewed. The combination of these tests provides a better understanding of the mechanism that controls the spontaneous combustion phenomena. However, irrespective of the extensive studies that have been conducted over time, spontaneous combustion is still a major problem in the coal value chain.
基金financially supported by the National Science Fundamental of China Projects(Nos.41072115 and 51174262)the project of the Science Foundation of Hebei(No.D2011402034)
文摘Total 138 coal samples and 14 parting samples were taken from the No. 6 Seam of the Jungar Coalfield, Inner Mongolia. These samples were analysed by optical microscopy, sequential chemical extraction procedure (SCEP), inductively coupled plasma mass spectrometry (ICP-MS), X-ray powder diffraction (XRD), and scanning electron microscope in conjunction with an energy-dispersive X-ray spectrometer (SEM-EDX) analysis. The results indicate that the Li contents have reached the industrial grade of the coal associated Li deposit, and the total Li reserves have reached 2406600 tons, that is, 5157000 tons Li2O in the No. 6 seam in the Jungar Coalfield. The sequential chemical extraction procedure results suggest that the Li concentration is mainly related to inorganic matter. The minerals in the coals consist of kaolinite, boehmite, chlorite-group mineral, quartz, calcite, pyrite, siderite and amorphous clay material. Some Li could be absorbed by clay minerals in the Li-bearing coal seam. The chlorite phase?could be?most likely the host for a part of Li. The Yinshan Oldland should be the most possible source of Li of the coal.
文摘This paper discussed the petrographic characteristics of No.6 coal from the Xiaoyugou mine,Jungar Coalfield,Ordos Basin,China.10 samples(7 coal,1 parting mudstone and 2 floor mudstone)were analysed by microscopical and geochemical methods.Four maceral compositions and several associated elements parameters were selected as indicators and corresponding diagrams were drawn to explicate the sedimentary environment.The results indicate that the maceral is dominated by vitrinite and minerals are mainly kaolinite in the No.6 coal.The sedimentary facies vary from barrier island system to tidal-flat which is a deposition process of water body shallowing and the coal-forming plants are herbs and woody plants formed in swamps.
基金supported by the China geological survey project"Qaidam Basin Oil and Gas Resources Evaluation"(Nr:([2013]4-(3),001-008)National Natural Science Foundation of China(No.41330317)
文摘Total of 23 bench samples were taken from the No. 7 Coal of Iqe Coalfield, Qinghai Province, China, following Chinese Standard Method GB/T 482-2008 (2008). These samples were analyzed by powder X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP- MS) and X-ray fluorescence (XRF). The results indicate that the No. 7 Coal belongs to a low rank (Ro.ran =0.659%) and high-ash coal (40.54%). Compared to common Chinese and world low-rank coals, the lqe coal contains anomalous concentrations of rare metal elements, rare-scattered (dispersed) elements and rare earth elements. The highest contents of Rb, Cs, Ga and REY reach to 180, 26, 37, and 397 ppm, respectively. Their average contents of these elements are 10.9, 15, 4.8 and 3.5 times higher than those of world coals, respectively. Minerals in the coal include kaolinite, quartz, muscovite, siderite, and traces of rutile, and brookite. Kaolinite could be main host minerals of Rb, Cs, Ga and REY. The anomalous rare element Rb and Cs accumulation in the Iqe coal is related to both organic and inorganic matter. The REY concentrations may be related to circulation of thermal solutions, contained or sorbed by clayey particles, and organic matter as well.
基金National Natural Science Foundation Project (Grant No. 41662010)Xinjiang Uygur Autonomous Region University Scientific Research Program For Young Teachers Research And Cultivation Fund Project (Grant No. XJEDU20I6S038).
文摘Santanghu Coalfield is the largest integrated coalfield exploration area in China. The major coal seams developing in Xishanyao Formation (Middle Jurassic) are the high-quality steam coals characterized by large thickness, favorable horizontal continuity and high coal quality. In this paper, twenty-two samples were collected from the three typical boreholes in Hanshuiquan disirict, representing the 11 coal seam sequences (7#,8#,9#,13#, 14#,15#,17#,18#,19#,20#,22#), respectively. The petrographic characteristics of the coal-bearing sequence in Xishanyao Formation were firstly summarized systematicly, and then the coal-forming swamp characteristics and succession mechanism of the coal seam in Xishanyao Formation were defined by analyzing the samples. The maceral composition, structure, geochemical and geophysical characteristics of coal are in eluded in original genetic criteria of coal-forming swamp an alysis. And the composition of coal petrography, maceral and microlithotype are the most frequently used parameters. Coal is composed of microscopic constituents and inorganic substances. The Xishanyao Formation maceral mainly consists of vitrinite (65.74%-97.01 %), inert i nite (1.93%-34%), and the exinite shows the mode of regular change. The coal-forming swamp in Xishanyao Formation possesses the characteristics of mainly marsh, wet forest swamp facies, and shallow water covered forest swamp facies, and a few of coal seams distribute in the deep water covered forest swamp facies. In addition, the sporopollens in Xishanyao Formation are mainly Pinaceae evergreen broad leaf and needle-leaved plants. Osmundaceae, Cyatheaceae and Lygodiaceae, indicating that the warm and humid tropic-subtropical climate conductive to the persistent growth of coal-forming plants in the Middle Jurassic. The coal-forming swamp shows the characteristics of vertically upward fluctuation through the periodic transition. It indicates a shallow-deep-shallow change process of the water covered depth in the swamp. This is the prin ci pal factor for the formation of the high-quality and continuous coal seam in Hanshuiquan district, Santanghu Coalfield.
基金funded by Coaltech and is part of a PhD research/Postdoctoral study in the School of Mining Engineering at the University of the Witwatersrand
文摘Coal and coal-shale undergo low-temperature oxidation when exposed to air,potentially leading to spontaneous combustion.Coal-shale found in association with coal seams vary considerably in their intrinsic properties and spontaneous combustion liability index.Fourteen coal-shale samples collected from four different coal mines in Witbank Coalfield,South Africa,were experimentally investigated.The influence of coal-shale intrinsic properties and spontaneous combustion liability indices(determined by the WitsEhac Index and the Wits-CT Index)were established.The liability indices indicate relationships with the intrinsic factors and thus,identifying the major intrinsic factors affecting liability toward spontaneous combustion in these coal-shale samples.The XRF analysis indicated that the coal-shale samples are rich in Si O2,Al2O3 and Fe2O3,while the XRD showed that same coal-shale samples are generally dominated with kaolinite and quartz.The coal-shale occurred in association with medium Rank C bituminous coal and contained varying proportion of macerals.The Wits-Ehac Index was unable to reliably determine liability indices of some coal-shale samples,and hence the Wits-CT Index was developed.The results obtained from the characterisation tests may be used as a tool to predict the spontaneous combustion liability in carbonaceous material and may serve as a reference when comparing coal-shale from different coal mines.
文摘Based on the systematic analysis of the coal gangue in Weibei Coalfield, such as petrologic characteristics, chemical composition, nutrient elements, deleterious elements, and the transformation, and compared with the soil element content background values of Loess Plateau and national harmful materials controlling standards, we conclude that the coal gangue in the Weibei Coalfield has huge potential to be used as clay fertilizer.
文摘In this paper,the spatio-temporal variation and propagation direction of coal fire were studied in the Jharia Coalfield(JCF),India during 2006–2015 through satellite-based night-time land surface temperature(LST)imaging.The LST was retrieved from Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)night-time thermal-infrared data by a robust split-window algorithm based on scene-specific regression coefficients,band-specific hybrid emissivity,and night-time atmospheric transmittance.The LST-profile-based coal fire detection algorithm was formulated through statistical analysis of the LST values along multiple transects across diverse coal fire locations in the JCF in order to compute date-specific threshold temperatures for separating thermally-anomalous and background pixels.This algorithm efficiently separates surface fire,subsurface fire,and thermally-anomalous transitional pixels.During the observation period,it was noticed that the coal fire area increased significantly,which resulted from new coal fire at many places owing to extensive opencast-mining operations.It was observed that the fire propagation occurred primarily along the dip direction of the coal seams.At places,lateral-propagation of limited spatial extent was also observed along the strike direction possibly due to spatial continuity of the coal seams along strike.Moreover,the opencast-mining activities carried out during 2009–2015 and the structurally weak planes facilitated the fire propagation.
基金supported by the National Natural Science Foundation of China(51974275)the Tianshan Innovation Team of Xinjiang Province(2021D14018)the Natural Science Program of Xinjiang Province Department of Education(XJEDU20181007).
文摘Coal spontaneous combustion(CSC)is a disaster associated with coal mining that leads to loss of coal resources and envi-ronmental and human health issues.To investigate kinetic characteristics for oxidation of coal,three coal samples were collected from different coal mining areas in the Southern Junggar coalfield.Subsequently,the collected coal samples were ground into different particle sizes and tested using microscopic and macroscopic methods,including thermal gravimetric analysis,Fourier transform infrared spectroscopy,X-ray diffraction,and temperature-programmed oxidation.The results obtained are as follows:the sharpest absorption peak(002)indicates that graphitization is high.Furthermore,the results show that the SKS coal sample is prone to spontaneous combustion;the greater the aromatic hydrocarbon content is,the more difficult it is for CSC to occur,while the opposite is true for oxygen-containing functional groups.The SKS data confirmed this conclusion;the rate for generation of CO and CO_(2)controlled the possibility of SKS oxidation at 110℃and provided an indication of the temperature.During the dehydration stage,the WD sample had the lowest activation energy,indicating that it was most susceptible to spontaneous combustion.During the combustion stage,the lowest activation energy was found for the SKS sample with particle sizes<0.075 mm,indicating that particle size was one of the factors affecting spontane-ous combustion.The activation energy for dehydration was significantly lower than that for combustion,which showed that the coal oxygen reaction was more likely to occur in the dehydration stage.Based on DSC curves,the SKS sample had the largest exothermicity,indicating that it would ignite more readily.
文摘Heavy mining of Jurassic and Carboniferous horizontal coal seams in the Datong coalfield has seriously affected the local geological environment, which is mainly manifested by such geohazards as soil avalanches, landslides, mudflows, surface subsidence, surface cracks, surface solid waste accumulation and surface deformation. More seriously, coal mining causes groundwater to leak. Overpumping of groundwater has resulted in substantial land subsidence of the urban area in Datong City. Based on the previous geo-environmental investigation in the work area, the authors used radar remote sensing techniques such as InSAR (synthetic aperture radar interferometry) and D-InSAR (differential synthetic aperture radar interferometry), supplemented by the optical remote sensing method, for geo-environmental investigation to ascertain the geo-environmental background of the Datong Jurassic and Carboniferous-Permian coalfield and evaluate the effects of the geohazards, thus providing a basis for the geo-environmental protection, geohazard control and prevention, land improvement and optimization of the human environment. In this study 8 cog-nominal ERS-1/2 SAR data frames during 1992 to 2003 were used, but the following processing was made: (1) the multitemporal SAR magnitude images were used to interpret the geological structure, vegetation, microgeomorphology and drainage system; (2) the multi-temporal InSAR coherent images were used to make a classification of surface features and evaluate the coherence change due to coal mining; and (3) the multi-temporal cog-nominal SAR images were used to complete D-InSAR processing to remove the information of differential deformation areas (sites). In the end, a ten-year time series of differential interferograms were obtained using the multi-temporal cog-nominal SAR images. In the tests, 84 deformed areas (sites) were obtained, belonging to those in 1993-1996, 1996-1997, 1997-1998, 1998-2001, 1998-2002 and 2001-2003 respectively. Of the 84 areas, 44 are mining subsidence ones, 23 urban subsidence ones and 17 landslide subsidence ones. They cover a total area of 1824.4 km^2, equivalent to the area of the whole Datong coalfield. Then an accurate evaluation was made on the geo-environment of the Datong coalfield. The tests show that InSAR is now the only feasible technical means for making one all-weather, real-time measurement of a coal mining land subsidence area covering up to 10,000 km^2 to subcentimeter resolution. This study is a successful application of InSAR in the investigation and evaluation of land subsidence, especially in coal mining areas.
基金This study was financially supported by the Geological Survey Project of China Geological Survey National Potential Evaluation of Coal Resources project(121211121043)the National Natural Science Foundation of China(41572141,41772156).
文摘The occurrence of coal-bearing strata in a variety of coal-bearing basins of China is characterized by late tectonic deformation and remarkable spatial and geochronologic differences.The main controlling factors,which determine the tectonic framework of coalfields,include the geodynamic environment,tectonic evolution,deep structures,tectonic stress,and lithologic combination of the coal measures.The Chinese continent has experienced multi-stage tectonic movements since the Late Paleozoic.The spatial and temporal heterogeneity of its continental tectonic evolution,the complexity of its basement properties,and its stratigraphic configurations control the tectonic framework of its coalfields’present complex and orderly patterns.The concept of coal occurrence structural units is proposed in this paper and is defined as the structural zoning of coal occurrence.China’s coalfields are divided into five coal occurrence structural areas,and the structural characteristics of the coalfields in five main coal occurrence areas throughout the country are summarized.Based on the analysis of the relationship between the structure characteristics and occurrence of coal in these coalfields,the coal-controlling structures are divided into six groups:extensional structural styles,compressional structural styles,shearing and rotational structural styles,inverted structural styles,sliding structural styles,and syn-depositional structural styles.In addition,the distribution of coal-controlling structural styles is briefly summarized in this paper.
基金the Key Research and Development Projects in Anhui Province(201904a07020071)the Science and Technology Project of the Department of Land and Resources of Anhui Province(2016-K-16)the Key Research and Development Projects in Anhui Province(1804a0802198).
文摘Based on analysis of a large data set and supplementary sampling and analysis for hazardous trace elements in coal samples from the Huainan Coalfield,a generalized contrast-weighted scale index method was used to establish a model to evaluate the grade of coal cleanliness and its regional distribution in the main coal seam(No.13-1)The results showed that:(1)The contents of Cr,Mn and Ni in the coal seam are relatively high and the average values are greater than 20μg/g.The contents of Se and Hg are at a high level while most other trace elements are at normal levels.(2)The cleanliness grade of the coal seam is mainly grade III-IV,which corresponds to a relatively good-medium coal cleanliness grade.However,some parts of the seam are at grade V(relatively poor coal cleanliness).(3)Coal of relatively good cleanliness grade(grade III)is distributed mainly in the regions corresponding to the Zhuji-Dingji-Gubei coal mines and in the eastern periphery of the Panji coal mine.Coal of medium cleanliness(grade IV)is distributed mainly in the regions of the Panji-Xiejiaji and Kouzidong coalmines.Relatively poor grade coal(grade V)is distributed in the southwest regions of the coalfield and the contents of Cr,As and Hg in coal collected from the relatively poor coal cleanliness regions often exceed the regulatory standards for the maximum concentration limits.
基金This work is financially supported by Mega-projects of Science Research for the 13th Five-year Plan:[Grant Number 2017YFC0804303].
文摘The history of coalfield geology and mine geology IT applications is over 30 years,which is gaining remarkable achievements.This paper sheds light on the development of geological and surveying spatial management information systems.Specifically,this study proposed the development trend,system structure and function design and sub-systems of the new generation of geological and surveying spatial management information system by benefitting from the recent advancements in computer and spatial information technologies.The sub-systems include the“One Map”online collaborative(2D-GIS)management platform,the geological survey mapping collaborative management system,the integrated service system based on“one map”,the three-dimensional dynamic geological model system,the three-dimensional transparent management platform,and water prevention and control information management system.This work is an important foundation to realize the IT information and intelligent management of coal industry.The successful development and application of the new generation of geological and surveying spatial management information system will provide the dynamic data support for the online decision-making of the intelligent coal mining.
基金supported by the National Natural Science Foundation of China(grants No.41373108 and 41602167)
文摘Igneous intrusion into coal-bearing strata can cause an abrupt increase of temperature-pressure and trigger hydrothermal circulation at the igneous rock-coal contact zone. The conductive heat of intruded lnagma and convective migration of secondary hydrothermal fluids have been observed to significantly alter the concentrations and modes of occurrence of mercury (Hg) in thermally-intruded coals.
文摘Adsorption isotherm relates the gas storage capacity as a function of pressure at constant temperature.In this paper,adsorption isotherm of two dry borehole samples was constructed in the laboratory using the manometric method.Isotherm was measured for two gases,i.e.,CH4 and CO2 to pressure up to 8.4 MPa.Before the construction of sorption isotherm,coal was characterized by proximate,ultimate and petrographic analysis.Coalbed gas content of these two samples was found 2.29 m3/t and 2.75 m3/t.SEM images were obtained for the pore size distribution of coal using pore image analysis.Prediction of coalbed methane recovery from CH4 adsorption isotherm showed that these coalbeds are under saturated.CO2 isotherm was constructed to estimate enhanced coalbed methane(ECBM)recovery.Volume wise CO2/CH4 sorption ratio was found 2.09 times to 2.75 times respectively.This paper presents the interpretation of isotherm data to find the recovery factor of methane production from Jharia coalfield.
基金funded by the Science and Technology Innovation Fund of Petro China(grant No.2014D-5006-0105)the National Natural Science Foundation of China(grant No.41273066)
文摘Shale oil occurs in free state (including condensate state), adsorption state (adsorbed on kerogen and mineral particles) and dissolved state (dissolved in natural gas, residual water, etc.) in shales and adjacent layers. The characterization of the occurrence of different hydrocarbons in shale oil, especially the quantitative separation of free hydrocarbons (mobile oil), has been the current focus of shale oil research. Taken the shale oil from the Muli coalfield in Qilian Mountain as an example, this work extracted shale samples with organic solvents of different polarity to obtain different occurrence states of hydrocarbons in the oil-bearing shale and to reveal the compositional differences of the hydrocarbons. The result may provide new geochemical information for the occurrence and mobility of shale oil.