The effect of a conductive overburden on the electromagnetic response of a horizontal loop prospecting system to a tilted half-plane conductor is investigated by the analog modelling. It was found that the superficial conductive layer affects the anomaly by causing: a)appearance of an extra peak in the quadrature; b) base level shift of the profiles; c) phase rotation - consequently resulting in reversion of the quadrature -; and d) amplitude reduction. The appearence of an extra peak in the quadrature component complicates the quantification of the anomaly but, on the other hand, it may provide a useful information about the dip and induction number of the orebody as well as that of the overburden. The results assembled in the form of Argand diagrams can be used for a quantitative interpretation of an EM anomaly to estimate the  conductante, depth and dip of the conductor.Resumo indisponível.