You are being redirected because this document is part of your ASTM Compass® subscription.
This document is part of your ASTM Compass® subscription.
Chapter 1 | Classification of Coals by Rank
For RefWorks, EndNote, ProCite, Reference Manager, Zoteo, and many others.
For Microsoft Word
Because of the worldwide occurrence of coal deposits, the numerous varieties of coal that are available, and its many uses, several national coal classification systems have been developed. These systems often are based on characteristics of domestic coals without reference to the coals of other countries. The terms for describing similar or identical coals are not uniform among these various systems.Efforts in the United States and worldwide have been made to develop systems for classifying coals that are based on characteristic properties determined by laboratory methods. Attempts have also been made to develop an international system for classifying coals to eliminate confusion in international trade and to facilitate the exchange of technical and scientific information related to coal utilization and research. A discussion of the system used for classifying coals in the United States and the international systems of coal classification follows.In the ASTM International (previously the American Society for Testing and Materials) Standard D388, Classification of Coals by Rank , coals are classified according to their degree of metamorphism (i.e., progressive alteration) in the natural series from lignite to anthracite. The basis for the classification is according to fixed carbon and calorific values calculated on the mineral-matter-free basis. Higher-rank coals are classified according to fixed carbon on the dry mineral-matter-free basis. Lower-rank coals are classified according to their calorific values on the moist mineral-matter-free basis. The agglomerating character is also used to differentiate certain classes of coals.