Foreword

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This document was prepared by Technical Committee ISO/TC 27, Coal and coke Subcommittee SC 5, Methods of analysis.

This fourth edition cancels and replaces the third edition ( ISO 7404-1:2016 ), which has been technically revised.

The main changes are as follows:

input from the International Committee for Coal and Organic Petrology (ICCP) has been added;
several terms and definitions have been added or modified;
information supporting the vocabulary has been restructured as Annex A.

A list of all parts in the ISO 7404 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

Petrographic analyses have been recognized internationally as important in the context of the genesis, vertical and lateral variation, continuity, metamorphism and usage of coal. The International Committee for Coal and Organic Petrology (ICCP) has made recommendations concerning nomenclature and analytical methods and has described in detail the characteristics of a wide range of coals.^[ 1 ^][ 2 ^][ 3 ^][ 4 ^][ 5 ^][ 6 ^] This document incorporates many useful comments made by members of the ICCP and by member bodies of ISO/TC 27.

Petrographic analyses of a single coal provide information about the rank, the maceral and microlithotype compositions and the distribution of minerals in the coal. The reflectance of vitrinite is a useful measure of coal rank and the distribution of the reflectance of vitrinite in a coal blend, together with a maceral group analysis, can provide information about the rank and type of the coal and important chemical and technological properties of the blend.

The ISO 7404 series is concerned with the methods of petrographic analysis currently employed in characterizing coal in the context of its technological or geological use, or both. It establishes a system for petrographic analysis.

This document is intended for use solely in connection with the generally accepted international methods of petrographic analysis of coal described in the other parts of the ISO 7404 series .

The petrographic terms listed herein are those used by the ICCP and ISO. They do not include terms such as, for example, pseudovitrinite, semi-vitrinite and semi-inertinite which refer to types of maceral with particular properties, but which are sometimes difficult to define. Such terms can be considered important for specific applications, but their wider use is not recommended.

1 Scope

This document 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 and types.

This document 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.

2 Normative References

3 Terms and definitions

3.1 General

3.2 Terms related to optical microscopy

3.3 Terms related to petrography

Bibliography