An in-depth interpretation of definition and classification of macerals in coal (ICCP system 1994) for Chinese Researchers,III:Huminite

The huminite classification system of lignite was published in 2005 by International Journal of Coal Geology.The definition and classification of huminite of the “ICCP System 1994” are of special significance for the Chinese researchers because there is no Chinese national standards of maceral classification for the low-rank coal.In the classification “ICCP system 1994”,the huminite has been revised from the previous classification to accommodate the nomenclature to changes in the other maceral groups,especially the changes in the vitrinite classification.The huminite in the classification system is subdivided into three maceral subgroups,telohuminite,detrohuminite and gelohuminite;each of the maceral subgroup is divided into two macerals,which are further subdivided into submacerals and even maceral variety.Although this classification system is mainly for lignite (low-rank coals with huminite reflectance less than 0.4%),it is practically applicable to lignite and subbituminous,because the vitrinite and huminite classification of “ICCP system 1994” have been correlated so that down to the level of sub-maceral groups.Therefore,the two classifications can be used in parallel.At the level of macerals and for finer classifications,the analyst now has,according to the nature of the coal and the purpose of the analysis,a choice of using either of two classification systems for huminite and vitrinite.This accordance with the new ISO Coal Classification that covers low-rank coals as well and allows for the simultaneous use of the huminite and vitrinite nomenclature for low-rank coals.