Vitrinite classes

Table 2. Vitrinite Reflectance Limits, Taken in Oil, and ASTM Coal Rank Classes ...

Low volatile bituminous coal rank and heating values, 6 726t vitrinite reflectance limits and ASTM coal rank classes, 6 708t Low volatile bituminous coal grade (U.S.), 6 713t... 

Vitrinite type reflectance classes of vitrinite that span 0.1% reflectance intervals... 

Figure 1. Photomicrograph of a polished surface of a bituminous coal. Representatives of the three major classes of maceral materials are identified (V), vitrinite (L), liptinite (I), inertinite.

Because of the complexity of the coalification processes, different measures are used to define different levels of rank (Table I) high moisture, low heating value, and nonagglomerating character of the coal define the rank (group) within the lignite and subbituminous classes and volatile matter (or fixed carbon) define the various groups of rank in the bituminous and anthracite classes. In addition to these properties, the reflectance of vitrinite, carbon content of the coal (dry, mineral matter free), and some other properties change proportionately as rank increases (Table I). 

Figure 2 Histograms of the distribution of vitrinite in reflectance classes for a bituminous coal (A) and a complex coal blend (B).

Fusain consists of opaque to translucent irregularly shaped masses. On the other hand, the microscopical examination of polished coal carried out under reflected light, a methodology first initiated in France, led to four different classes also called lithotypes (macerals) vitrain, clarain, durain, and fusain. Each group is characterized by a particular reflectivity and aspect. The major maceral groups are vitrinite, exinite and inertinite. 

The overall ASTM D-388 [13] classification scheme is presented in Table 3.4 and values for the mean random reflectance of vitrinite and bed moisture are also added [3], There are four main classes of coal distinguished with gradual... 

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