The southeastern part of the Slave craton offers high potential for diamonds as well as possibly for base and precious metals. However, the geology at the surface and geophysical properties at depth are poorly known compared to other parts of the craton, notably the Lac de Gras region. The Walmsley Lake project addresses this deficiency with collocated bedrock, isotope and geophysical data acquisition. This paper describes the initiation of the deep geophysical component of the project, and presents the preliminary qualitative results of the data from the magnetotelluric component. The main result at this early stage is the discovery of a large conductivity anomaly, likely within the Thelon-Talston Magmatic Zone, comparable to the North American Central Plains (NACP) conductivity anomaly.