A brief description is given of computation modeling and experimental field work on the inductive resistance method based upon a study of transitional processes in the magnetic field. The computation-modeling technique makes it possible to prospect efficiently highly conductive ores. A block-diagram of the apparatus for investigating transitional processes under field conditions is shown. For three deposits it is shown that commercial pyrite occurrences are definitely localized in recording transitional processes. A study of late stages of transitional processes makes it poss ble to eliminate almost fully the influence of enclosing and overlying rocks and to record only anomalous effects of highly conductive ores. —Auth. English summ.