The aim of the MT studies was to investigate crystalline bedrock for geothermal resources exploration. Geopartner performed both MT surveys and their interpretation. Magnetotellurics is the only available geophysical method which allows to recognize igneous and metamorphic rocks at great depths and in hard mountainous terrain. In the described case, performed surveys allowed to define geological model of the Giant Mountains massif to a depth of 2 km bgl. Interpretation of electrical conductivity zones from MT data enabled to plan the optimal location of geothermal boreholes.