Comparison of 3D conductivity imaging from multiple EM surveys

It is now possible to invert frequency and time domain data to recover 3D conductivity models. The San Nicolas deposit makes an ideal test site because much is known about the deposit and also many different types of survey data have been collected there. In particular DC resistivity, 3D controlled source frequency domain data, and UTEM data have been acquired. We have inverted each of these data sets. In this talk we describe the data sets and the methodologies for inversion and compare the resultant models. The DC resistivity data were not able to see the deposit because of the conductive overburden, but both the frequency and time domain inversions produced a good image of the primary mineralized zone.