| Multivariate statistical techniques have been used to study interrelationships among 12 variables within a data set for 277 coals representing whole-seam channel, column, and core samples obtained from the 6 coal provinces of the United States, and varying in rank from lignite to anthracite. The data are maintained in a computerized data base at The Pennsylvania State University Coal Research Section. The variables chosen are components of the elemental analysis, selected components of the proximate analysis (volatile matter and moisture), calorific value, reflectance of vitrinite, and the relative proportions of the 3 maceral groups.;A reconnaissance study of selected ash components was strongly affected by a geographic sampling bias; Western coals contain high contents of calcium and magnesium oxides and low contents of potassium and iron oxides.;Analysis of variance indicated the following: within the Eastern Province older coals have attained a higher rank than younger coals; the coals from the Eastern, Interior, and Rocky Mountain Provinces for which more than 1 sample was obtained from individual mines have a variance within the mines which is inhomogeneous, precluding pooling of the data to investigate sources of variation between both mines and provinces; Paleocene age coals are significantly lower in rank than Cretaceous and Eocene age coals, a result which is attributed to a geographic sampling bias; and Interior Province coals of the high volatile bituminous rank range are significantly higher in moisture and lower in reflectance than coals of similar rank from the other provinces, but within the medium volatile bituminous rank range Interior Province coals differ only in that they possess significantly lower reflectances.;Cluster analyses indicated that the most significant partitioning produces 4 groups which are differentiated primarily on the basis of the following factors: rank, maceral composition, and organic sulfur content. These 3 factors are the most important independent sources of variation for the entire data set and for these subsets. Factor analyses of these individual groups, of 5 classifications of coal grouped by ASTM rank, and of coals grouped by province provide insights into the coalification processes of these more homogeneous coal associations. |
