The Characteristics Of Deep-seated Coal Seams’ Rank/coal’s Structure And Coalification In Huainan Coalfield

The geological structure’s features of coal accumulating region in Huabei district arecomplex, and the differences of time and space of coal type’s distribution are huge. With theexhaust of the shallow coal resources from the coal mining areas in eastern Huabei district, itcame into a common view to exploration in deeper coal seams. The distribution characteristicsof deep-seated coal seams’ type have an effect on the China’s coking coal resources’ potentialin the future, so it would be realistic meaning to study the law of deep-seated coal seams’ typeand its coal metamorphism.This study take the Huainan coalfield located in the Anhui province in the eastern Huabeidistrict as an example, using a lots of scientific studing methods such as coal geology, coalpetrology, coal chemistry, tectonic geology and so on to systematic study the law of coal rankparameters’evolution, the characteristics of coal structure. Basing on using the reflection ofvitrinit as a subject matter for earth temperature, it was finished to recover the studying area’sburying history and heat history. Further, with considered the studying areas’ geologic settingand the works in burying history and heat history of predecessors, the control factors of thedeep-seated coal seams’ rank, coal structure and coal metamorphism were studied, whichwould be supposed have a positive effect on predicting the deep-seated coal seam’s rank ofHuabei coal accumulating region and the supporting development of coal metamorphism’s lawfor deep seams.Following are the main results and new points of this study.1. The Huainan coalfield is a huge coalfield with several coal types to be occurred in such asgas coal, fat coal, coking coal and lean coal. The gas coal type group occurred in shallow coalseams, and the fat coal and coking coal occurred in deep-seated coal seams. With the raising ofmodern burying depth, the coal rank in the whole studying area has the tendency of slowlyraising.2. The tectonic deformed coal of different degree were occurred commonly in the shallow and deep-seated seams in Huainan coalfield. The occurrence of tectonic deformed coal wascontrolled by the geologic factors as faults or bend. According to the deformed degree of coal,it came to a results that the stability of coal was raising, the packing degree and the ductility ofcoal’s basic union was increasing, the A branched structures of aromatic ring were breakingaway and the aromatic degree was increasing, which could be considered as a evidence oftectonic deforming having a positive effect on the coal rank in deep-seated coal seams.3.The coal metamorphism of Huainan coalfield is the normal metamorphism which has acharacteristics of muti-stages and affected by the tectonic press obviously. The impact ofmagma investing had a very less impact on Huainan coalfield. The partly contactingmetamorphism had a low level impact on coal seams’ rank and the rang is small. The results ofsimulation of the burying history and heat history of studying area show it experienced threestages of tectonic heat movement. The first stage is the normal metamorphism’s main part,which base the candle coal and gas coal rank for Huainan coalfield. In the second stage,Superposition of the effect of mountain folding in phrase of Yanshan, the coal’s metamorphismcontinued, and the coal rank of different coal mine became distinct for the reason of buryingspeed, depth and corroding degree. The metamorphism was supposed remain stagnant in thethird stage because of lower temperature. The differences of coal rank between the Panyicoal mine and Wangfenggang coal mine mainly occurred because of the strata’s sedimentationrate, bury depth and corroding degree in the first stage as well as the heat of well bottom in thesecond stage.