Expanding the reserve base of operating mines: Insights from an airborne MobileMT survey in the Omsukchan depression, Russian Far East

In the frame of expanding the reserve base for the Omsukchan mining district, an airborne electromagnetic survey was carried out over and around the Dukat silver giant. The initially developed exploration concept was based on weakly investigated deep structures controlling the epithermal mineralization in the region. The airborne electromagnetic technology, MobileMT, based on exploiting natural fields in the audio frequency range provided depth of investigation, in the geoelectrical environment, from near-surface up to, at least, 2.5 km. The areal resistivity mapping data over the regional trough structure provides valuable insights on deep dome structures and following subvertical feeding and transporting zones which control the silver-polymetallic mineralization. The position of around 20 known deposits and occurrences was analysed in relation to numerically derived resistivity models. The results of the empirical analysis are used for identifying prospective zones for new discoveries.