We have studied 2,035 samples from the Appalachian bituminous coal beds, 370 samples from the eastern interior coal beds, and 362 samples from the Rocky Mountain coal beds.

The coals analyzed range in rank from high-volatile bituminous to low-volatile bituminous; the Appalachian coals have the lowest mean volatile-matter and moisture contents and the highest fixed-carbon content and Btu value. The Rocky Mountain coals have the highest mean ash content and lowest fixed-carbon content and Btu value. The average Appalachian coal has a much higher rank than does coal from either of the other regions.

Of the 19 elements reported, seven (Cu, F, Mn, Pb, Sb, U, and V) have mean values that vary less than twofold among the three areas. Of these, U is the most uniformly distributed. Other elements (Co, Ni, Zn, and S) have about a fourfold variation, whereas As is 6.5 times as abundant in Appalachian coal as in Rocky Mountain coal. In average, the other elements are 2 to 6.5 times as abundant in some coals from the three areas

Table

as in others.

The Rocky Mountain coals have the lowest mean contents of 15 of the elements listed in the table; only U and F mean contents are slightly higher in this area. The eastern interior coals have the highest mean contents of nine of the elements, and the Appalachian coals have the highest mean contents of eight of the elements.

As the average rank of the coals increases, the average contents of As, Co, Cr, Cu, Hg, Se, and V also increase; however, the distribution of most other elements is not related to rank. In general, the trace-element content of coal is influenced largely by the depositional environment and does not depend on rank.

End_of_Article - Last_Page 761------------