A new efficient method is proposed for the electromagnetic induction monitoring of heterogeneous rock masses exposed to intense anthropogenic impacts. This method is based on the theory of 3-D interpretation of alternating electromagnetic fields. The efficiency of its application to the study of rock masses beneath the surface and identification of the structure and state of a rock mass is demonstrated with the use of in situ observations. This study revealed two types of parameters that characterize the rock mass as a whole, are sensitive to local variations in the rock mass and its potentially hazardous zones, and should be continuously monitored with the help of additional geophysical and geomechanical methods.