The electrical method is used with sucess to avaliate the limits of the areas containing iron formations in the districts of Nova Era - Itamarandiba, State of Minas Gerais. The electrical soundings on the other hand, help in avaliating the thickness of those formations. This uncommun applicability of the resistinty method is due to the existence of a more conducting weathered gneiss underlying the iron formations. It can be distinguished by means of that technique four 'eletrical' strata: the soil (low resistinty), iron formations (high resistinty), weathered gneiss (low resistinty) and sound rock (high resistinty).
