Keyword: «free moisture»

This arcticle presents a hypothetical model of transformation of the porous structure of coals’ organic matter of under the influence of negative temperatures. The model takes into account various scenarios of freezing and thawing of inner water, including either the formation of additional cracks and collectors, or with the «collapse» of micro- and mesopores. The results are presented on experiments related to the study of the effect coals of different genetic types with respect to a degree of vitrinite recovery during single freezing-thawing at different temperatures (-20, -40 and -60 °C) on their mechanical strength. It is shown that for coals of genotype I characterized by high heterogeneity of structure, the processes of freezing-thawing at different temperatures lead to an increase in the mechanical strength, which may be caused by the effect of compaction of organic matter due to the effect of «collapsing» of micro- and mesopores.