Coal Reserves of the United Stat 



ES 



131 



LIGNITE., CROCKETTTEX. 



FIXaO C/fRBON MOISTUKE ASH 



LIGNITE.. GLEN DIVE, MONT. 



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VOLATILE MATTEfl 



SUB-BITUMINOUS. LAFAYETTE, COLO. 



SUB-BITUMINOUS. GALLUP, N.MEX . 



BITUMINOUS. CARTERVILLE.ILL. 



SEMI -BITUMINOUS. POCAHONTAS, W.VA. 



SEMI-ANTHRACITE. SPADRA. ARK. 



ANTHRACITE, PENNSYLVANIA 



Diagram Showing the Progressive Change in Composition of L,ignite, Bituminous 



and Anthracite 



Note that all the moisture andjvolatile matter has been expelled in the anthracite 



into three main classes — anthracite, 

 bituminous, and Hgnite; but in the trade 

 these main classes are broken up into 

 several groups, which are represented in 

 the following diagram : 



DIAGRAM SHOWING CI,ASS OF COAI, 



Anthracite. . 



f (a) Anthracite. 



(6) Semi-anthracite. 

 ■ (c) Semi-bituminous. 

 " ■ I Bituminous. . . \ (d) Bituminous. 



y[e) Sub-bitummous. 

 [ Lignite (/) Lignite. 



(a) Anthracite coal is too well known 

 to need description, {b) Semi-anthra- 

 cite is a low grade of anthracite, (c) 

 Semi-bituminous is a high grade of 

 bituminous, such as the George's Creek 

 coal of Maryland, Pocahontas coal of 

 Virginia and West Virginia, and the 

 Carboniferous coal of Arkansas, {d) 

 Bituminous is the common grade of coal 

 found throughout the eastern coal fields 



and in limited areas in the west, {e) 

 Sub-bituminous is applied to coals below 

 the grade of bituminous, but above that 

 of lignite. They are black and shining, 

 but are light in weight and slack badly 

 on exposure to the atmosphere. These 

 coals are common in the western fields 

 of Washington, eastern part of Montana, 

 northern Wyoming, about Denver in 

 Colorado, and in northwestern New 

 Mexico. (/) Lignite is brown and 

 woody, and occurs in North Dakota, 

 South Dakota, Texas, southeastern Ar- 

 kansas, Mississippi, and Alabama. 



THE REASON WHY ONE COAL WILL COKE 



AND ANOTHER WILL NOT IS 



NOT UNDERSTOOD 



The classes noted above include all of 

 the different kinds of coal that are 

 known, but certain pecuHarities of coals 

 within the bituminous class have led to 



