Papers - Occurance - Anthracites and Semianthracites in the United States

Anthracite coals have been divided into three groups: (I) meta-anthracite, a high-carbon coal that is usually very slow to kindle and difficult to burn, at least on conventional equipment; (2) anthracite, a high-carbon low-volatile coal of widely accepted value as both a domestic and industrial fuel; and (3) semianthracite, a coal lying between anthracite and bituminous coal in carbon and volatile content, and also, generally speaking, in burning characteristics. Anthracite Groupings The technical differentiation between these groups, as defined by the A.S.A.-A.S.T.M. Sectional Committee on the Classification of Coals, is as shown in Table I. Tables 2 and 3 show typical analyses of anthracites and semianthracites and Figs. I to 3 show graphically the range of analytical samples. Table 4 shows the commercial sizes of coals. Meta-anthracite and Graphitic Anthracite Typical analyses from virtually every field in the United States indicate that there are few if any extensive deposits of meta-anthracite. Some of the anthracites of Rhode Island contain almost negligible quantities of volatile and would thus fall into the meta-anthracite grouping on a basis of analyses alone. However, their other characteristics indicate that it is doubtful whether they should be considered as fuels at all, but rather as graphite. In fact, this material is being mined for use as foundry facings and furnace linings.4 A typical analysis of Fenners Lodge graphite,4 from Rhode Island, is: graphitic carbon, 55.9 per cent; silica (ash), 40.6; sulphur, 1.6; moisture, 1.9; volatile, o. Other Rhode Island coals possess percentages of volatile that would throw them into the normal anthracite rather than the meta-anthracite class. However, this "volatile" is nearly all noncombustible,3,4 being composed almost entirely of carbon dioxide and inert gases, therefore its definition as volatile is open to discussion, leaving the exact classification of the fuel a moot question. One factor is certain, Rhode Island coal is so different from nor-mal anthracite in both analysis and burning characteristics that it should have a