Regularities of changes in solid fuel elemental composition during metamorphism have been investigated. A mathematical model describing these regularities as functions of C daf has been developed. Experimental data of artificial coalification confirm that it is an experimental model of natural metamorphism.

Dynamics of coal chemical structure during metamorphism has been evaluated using mathematical model of metamorphism kinetics attached to the time axis in accordance with artificial coalification data.

Jumps" in structure composition and properties of solid fuel have been determined using the model of metamorphism dynamics. For these "moments" of the geological age the elemental composition and structural peculiarities of "molecules" have been determined and approved by stoichiometric equations of the reactions, material balances of the stages and the agreement between the combustion heat of model compounds and coals of similar elemental composition.