Clean coal geology in China:Research advance and its future

In China,the connection between coal utilization and environmental pollution has been increasingly evident due to the rapid growth in energy consumption.Clean coal technology(CCT)is one of the effective methods to address coal-associated pollution.However,CCT needs the practical and theoretical support of clean coal geology(CCG).In this paper,a new definition of CCG is proposed,based on the definitions of coal,coal geology,and CCT,combined with the development of national CCG.CCG is the discipline comprehensively researching the genesis,nature,distribution,cleaning potential,clean utilization and environmental effects of resources(coal,coal bed methane,and other coal-associated resources)that can be cleaned by CCT.The research content of CCG is discussed from different aspects,such as cleaning potential evaluation,geological guarantee for coal mining,ash yields and sulfur contents,trace elements,pollution caused by coal,and mine reclamation.The progress of CCG in China is also briefly divided into four stages and delineated.Finally,scientific problems in CCG are summarized and an outlook for CCG is given.

The Status Quo and Outlook of Chinese Coal Geology and Exploration Technologies

Coal is China＇s dominant energy resource. Coal geological exploration is the basis of sustainable development of coal industry. Since the late 1990s, the advances in Chinese coal geology and exploration techniques have been shown in the following aspects. （1） The basic research of coal geology has changed from traditional geological studies to earth system science; （2） Breakthroughs have been achieved in integrated exploration techniques for coal resources; （3） Evaluation of coal and coalbed methane resources provides important basis for macropolicy making for China＇s coal industry and construction of large coal bases; （4） Significant advances have been made in using information technology in coal geological exploration and 3S （GPS, GIS, RS） technology. For the present and a period of time in the future, major tasks of Chinese coal geological technology are as follows： （1） solving resources replacement problem in eastern China and geological problems of deep mining; （2） solving problem of integrated coal exploration of complex regions in energy bases of central China, and resources problems induced by coal exploitation; （3） making efforts to enhance the level of geological research and resources evaluation of coal-accumulation basins in western China; （4） strengthening geological research of clean coal technologies; （5） strengthening geological research of the problems in modern coal mining and safe production; （6） promoting information technology in coal resources and major geological investigations.

Development history and prospect of remote sensing technology in coal geology of China

Coal remote sensing technology was founded in the period of coal resources survey after the founding of People’s Republic of China.Aerophoto Grammetry&Remote Sensing Bureau of China National Administration of Coal Geology was established,specializing in the application and promotion of coal remote sensing technology.With the rapid development of coal geological exploration in China,coal remote sensing technology has evolved from coal geology based survey to comprehensive survey that factors in resources,environment,ecology and so on.This paper summarizes the general situation,theories,development process,key research and future of remote sensing technology for coal mining in China.Spanning over 50 years,the history of China’s coal remote sensing technology can be divided into five stages:aero-geological mapping,coal remote sensing theory experimental research,application research and promotion,architecture planning and productionisation,“3S”technology integration and application.This paper expounds the main technical progress,application fields,major projects and major achievements in various historical periods,and points out that the coal remote sensing has entered a unified development stage of“Aviation,Aerospace and Ground”,with a focus on high-resolution remote sensing,hyperspectral remote sensing,radar remote sensing,“3S”technology integration and multi-means comprehensive exploration and evaluation.In the future,coal remote sensing technology will develop rapidly in data mass,technology integration,evaluation intelligence,integration application programming,system visualization,etc.Coal remote sensing technology has entered the industrial development from technology application.

Applications of Remote Sensing Techniques in Coal Geology

Through applied researches, the regularity of thermal infrared radiation of the coal seams has been found, a model of thermal radiation of the coal seams established, and the internal relations of the information extracted from remote sensing images with coal seams and coal measures revealed. Through a series of complete tests of remote sensing techniques such as multi-level (space, aerial and ground) synchronous remote-sensing and multi-directional, multiband and multitemporal remote sensing, the optimal procedure for applications of remote sensing techniques in coal geology has been determined. The theories and methods established in the applied researches have yielded apparent economic results and social benefits in respect to coal field prediction, coal reconnaissance, coal geological surveys and detection of geological hazards in coal mines.

THE REMOTE SENSING IN COAL GEOLOGY——A study on detection of coal spontanous burning by remote sensing in the coal fields in the north of China

The spontaneous burning has been lasting for thousands of years in the coal fields in the north of China. It spreads from the west (Tianshan coal field) to the east (Huolinhe coal field). Its E-W extension is up to 3750km, concentrating in N35°toN45°, its vertical depth up to 260m, and the surface temprature locally up to 270℃. Annually, it burns out 0, 250-300 million tones of coal, causing economic loss equivalent to 2-3 billion R.M.B. Yuan.It destroies coal resources and causes hazards in coal mines. In order to locate the extent and the direction in coal burning areas, the remote sensing technique has heen used and has produced an obvious benefit.

COAL GEOLOGY

20162559 Cheng Yuehong(Research Institute,CNOOC,Beijing 100028,China);Yang Zhiwen Coal-Accumulating Processes and Base Level Cycles of the Taiyuan Formation in the Datong Coalfield(Geology in China,ISSN1000-3657,CN11-1167/P,42(6),2015,p.1959-1968,6illus.,21refs.)Key words:coal measures,Shanxi Province Based on the base-level cycle principle,

COAL GEOLOGY

20161846 Chen Quanlin(Earth Science School,China University of Geosciences,Wuhan 430074,China)Characteristics of Detached Faults and Their Control on Coal in Longyong Coal Field(Coal Geology&Exploration,ISSN1001-1986,CN61-1155/P,43(4),2015,p.1-5,3illus.,10refs.)Key words:detachment faults,coal,Fujian

A review of the geomechanics aspects of a double fatality coal burst at Austar Colliery in NSW,Australia in April 2014

A coal burst occurred on 15 April, 2014 at the Austar Coal Mine, located west of Newcastle, NSW,Australia. The burst resulted in fatal injuries to two men working as part of the mining crew at the development face. At the time, a continuous miner was being used to mine a longwall development gate road through heavily structured coal, at a depth of approximately 550 m. A number of pre-cursor bumps had occurred on previous shifts, emanating from the coal ribs of the roadway, in proximity to the coal face.This paper reviews the geological, geotechnical and mining conditions and circumstances leading up to the coal burst event; and presents and discusses the available evidence and possible interpretations relating to the geomechanical behaviour mechanisms that may have been critical factors in this incident. The paper also discusses some key technical and operational considerations of ground support systems and mining practices and strategies needed for operating in such conditions in the future.

Geochemical and mineralogical evaluations of coal,shale,and mine waste overburden from Makum coalfield of the Northeast India

The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.

Bacterial degradation of coal discard and geologically weathered coal

The biodegradation of coal discard is being intensively studied in South Africa in an effort to develop passive methods for the successful revegetation and rehabilitation of waste dumps, to mitigate pollution, and facilitate mine closure. Bacteria were isolated from slurries of coal tailings and diesel-contaminated soil, screened for coal biodegradation competence, characterized, and the colonization and degradation of coal discard and geologically weathered coal investigated using individual isolates and consortia. Ten novel coal-degrading bacterial strains were isolated and characterized, the gene sequences deposited with GenBank, and the (wild-type) strains deposited at Microbial Culture Collection, India. The results from the present work show that bituminous coal discard and geologically weathered coal is used by these isolates as carbon and energy source. Isolated strains and consortia colonized and degraded both coal substrates. Growth rate of the isolates is faster and stationery phase achieved sooner in minimal medium containing geologically weathered coal. This observation suggests that the oxygen-rich weathered coal is a more friable substrate and thus readily colonised and biodegraded. A reduction in mass of substrate is demonstrated for both individual isolates and consortia. The changes in pH and associated media colouration occurred concomitant with formation of humic acid-like (HS) and fulvic acid-like substances (FS) which is confirmed following analysis of these products by FT-IR spectroscopy. It is concluded that preferential metabolism of alkanes from the coal substrates provided the carbon and energy for bacterial growth and transformation of the substrates to HS and FS.

Plastic zone analysis and support optimization of shallow roadway with weakly cemented soft strata

Based on a shallow roadway with weakly cemented soft strata in western China, this paper studies the range and degree of plastic zones in soft strata roadways with weak cementation. Geological radars were used to monitor the loose range and level of surrounding rocks. A mechanical model of weakly cemented roadway was established, including granular material based on the measured results. The model was then used to determine the plastic zone radium. The predicted results agree well with measured results which provide valuable theoretical references for the analysis of surrounding rock stability and support reinforcing design of weakly cemented roadways. Finally, a combined supporting scheme of whole section bolting and grouting was proposed based on the original supporting scheme. It is proved that this support plan can effectively control the deformation and plastic zone expansion of the roadway surrounding rock and thus ensure the long-term stable and safe mining.