The rocks of the oil shale formation of the Baltic basin, of which the Estonian deposit is a part, are characterized by three features that complicate both the determination of physical and mechanical properties of rocks and the study of the process of destruction of the massif by the action of explosion: 1) oil shale is not an isotropic body, but a finely layered medium; 2) the high clay content and porosity of both oil shale and some limestone interlayers make them highly plastic; 3) the presence of moisture and limestone inclusions in oil shale layers makes oil shale be considered as a multicomponent medium. ..