The Geotech VTEM time domain helicopter EM system

Abstract

The Geotech Ltd. VTEM heli-time domain EM system entered into commercial service in late 2002 after a development program that started in early 2001. Since then, the system has performed surveys in Canada, the USA, Brazil and southern Africa for a range of mineral deposit styles in a variety of geological settings. The VTEM system bears similarity to many of the past and currently operating heli-time domain system designs but has focused more than other developments on operational simplicity and flexibility in how the system is configured. A very high dipole (coupled with very low system noise levels) is deemed a major differentiating factor of the system compared with others in current operation. In terms of applications, VTEM is seen as an effective bridge between existing airborne electromagnetics technologies, combining the high spatial resolution associated with helicopter systems but with a depth of investigation similar to what fixed wing time domain systems were traditionally required to achieve.