Design, construction, and initial testing of a novel three-component electromagnetic transmitter system for deep mineral exploration

Electromagnetic (EM) methods are used in mineral exploration to detect conductive ore bodies. The ability of an EM system to detect geological targets at depth is partly dependent on the coupling the interaction between the transmitter’s primary magnetic field and the target conductor which is highly dependent on the target’s orientation. A novel three-component transmitter (3CTx) EM system was developed for ultimate implementation in airborne, semi-airborne, or ground systems. Its additional transmitter coils and multiple transmitter locations could provide a greater signal-to-noise ratio for deep geological bodies, while the co-orthogonal coils and resultant multiplicity of primary-field directions increased coupling with a wide range of target orientations. A prototype 3CTx system was designed, constructed, and field-tested. The primary objective was to validate the fundamental concept: that signals from the three transmitters could be acquired simultaneously by a receiver and then successfully separated during processing. Initial results from three field tests demonstrated that the individual transmitter signals could be separated with minimal cross-coupling, producing data comparable to that from a conventional single-component ground-loop system. This success validated the methodology, a crucial first step toward developing a full-scale system for deep exploration.