ISO/TC 27/SC 5/WG 14 - Petrographic analysis of coals

ISO 7404-4:2017 specifies a method, using a graticule with 20 crossline intersections, for determining the proportions of microlithotypes, carbominerite and minerite in coals. It applies only to determinations made on polished particulate blocks using reflected white light (about 400 nm to 700 nm). Additional blue, blue-violet or UV light excitation (365 nm to 440 nm) for better identification of liptinite in fluorescence may be used especially at low rank coals.

ISO 7404-1:2016 defines terms that are used in connection with both maceral and microlithotype analyses, and with the determination of the reflectance of vitrinite. It applies to the terms used in the examination of coal of all ranks. ISO 7404-1:2016 is not intended to be a comprehensive glossary of coal petrographic terminology, nor does it attempt to provide sufficient information to allow recognition of all the coal components described. Further information may be obtained from the relevant ICCP publications[3][4][5].

ISO 7404-3:2009 specifies a method for determining the proportions of the maceral groups (and the minerals, if desired) in coals. ISO 7404-3:2009 is applicable only to determinations made on polished particulate blocks using incident white light. For lower-rank coals, the additional use of the fluorescence mode is necessary to identify liptinites.

ISO 7404-2:2009 specifies methods for preparing a polished particulate block from a sample of crushed coal for analysis by reflectance microscopy. These methods can also be applied to the preparation of a polished, embedded lump of coal.

ISO 7404-5:2009 specifies the methods for determining the reflectance of vitrinite of coals microcopically on the polished surfaces, immersed in oil. The methods are applicable to coals from single seams or coal blends covering the whole range of low-, medium- and high-rank coal. Vitrinite reflectance measurements can be used to characterize the components within blends. Measures can be taken to correct for the vitrinite percentage within each of the components of the blend or to determine the proportion of components in a blend, particularly when the components have dissimilar vitrinite contents. This method necessitates the identification of vitrinite by the analyst. Reflectance measurements on vitrinite obtained by interpreting the results from an automated system, are outside the scope of ISO 7404-5:2009.

Cancels and replaces the first edition (1984). Specifies the method for determining microscopically the maximum and random reflectance in oil of polished surfaces of the vitrinite component of coals. Applicable to either coals from single seams or coal blends covering the whole range of bituminous coal and anthracite.

Cancels and replaces the first edition (1984). Defines terms that are used in connection both with maceral and microlithotype analyses carried out in white light and with the determination of the reflectance of vitrinite. Applies to the terms used in examination of bituminous coal and anthracite only. Not concerned with the analysis of brown coal, sub-bituminous coal or lignite.

Cancels and replaces the first edition (1984). Specifies a method of determining the proportions of the maceral groups (and the minerals if desired) in coals. Concerned only with determinations made on polished particulate blocks using reflected white light. Not concerned with the determination of the proportions of naturally occurring maceral associations.

This part of ISO 7404 applies only to determinations made on polished particular blocks using reflected white ligth. The examination is carried out by using reflected ligth microscope and point count procedure. The microlithotypes are identified from their maceral composition under an immersion medium. The proportions of the macerals are determined using a graticule having a grid with 20 points of intersection.