Composition, structure, and properties of Donetsk Basin and United States coal of the same metamorphic stage

The composition, structure, and properties of Donetsk Basin and United States coal of the same metamorphic stage are compared. The samples represent coal from the whole metamorphic series, with vitrinite reflection coefficient R _o = 0.7?C1.8%. Separate regression equations for Donetsk Basin and United States coal describe the relation between the composition (C ^daf , H ^daf , O ^daf ), structural characteristics (C_ar, f _a, ??, and B) calculated from the elementary composition, the technological properties (V ^daf , y, Q _s ^daf ), and the vitrinite reflection coefficient. Significant differences are found in these properties for Donetsk Basin and United States coal of the same metamorphic stage. These differences are mainly due to the different degrees of reduction of the coal. With a vitrinite reflection coefficient up to 1%, the degree of reduction is greater for United States coal than for Donetsk Basin coal. With greater metamorphic development (R _o ?? 1.0%), Donetsk Basin coal is characterized by even lower degrees of reduction.