Areal observation systems in combination with 3D-inversion based on direct 3D-modeling of transient electromagnetic fields in MTS and TEM methods provide the capability to use electromagnetic survey for volume reconstruction of ore clusters. Such reconstructions are based on use of profile-areal apertures, and differ in very high accuracy of the predicion of distribution of matter in studied volume in the parameter of electric resistance and are an irreplaceable basis for the effective geological forecast.
Usually reconstructed geoelectric model shows good correlation with geological representations and drilling results. On fig. 1 the areal distribution of transient field signal from the fixed M-TEM source near Karamkensky gold-bearing cluster is presented.
Fig. 1. Areal distribution of measured M-TEM signal from the fixed loop source (1000 х 1000 м2) near zone of Karamkenskyi gold-bearing ore cluster.
a) anomalous field t=1ms, b) anomalous field t=5ms, c) anomalous field t=15ms
Fig. 2. Volume geoeletrical model of the ore cluster obtained by 3D-interpretation of areal EM soundings (M-TEM)