Technical Papers - Airborne Electromagnetics

A Helicopter Time-Domain EM System Applied to Mineral Exploration: System and Data

David Fountain, Richard Smith, Tom Payne and Jean Lemieux (Fugro Airborne Surveys) describe recent progress in developing helicopter systems for time-domain airborne electromagnetic surveys, once the “domain” of fixed-wing aircraft.

Introduction

The first operational fixed-wing airborne electromagnetic (AEM) system was introduced in 1948 and was followed by the first operational helicopter AEM system in 1955 (Fountain, 1998; Fountain and Smith, 2003). There has been parallel development of both fixed-wing and helicopter AEM since that time and, up to the early 1960s, all these systems were frequency-domain. However, since the late 1970s, fixed-wing AEM systems have been primarily time-domain while the helicopter systems remained primarily frequency-domain. With the new millennium, and especially since 2002/2003, there has been significant development and introduction of helicopter time-domain AEM systems (Boyko, et al., 2001; Balch et al., 2003; Eaton et al., 2004; Sorenson and Auken, 2004; Vrbancich and Fullagar, 2004; Witherly et al., 2004). The pace of introduction has been such that, today, the number of time-domain systems in use is equal to the number of frequency-domain systems. Fugro Airborne Surveys and its predecessor companies have been leaders in the continuing development of fixed-wing AEM systems, including the introduction of the GEOTEM, MEGATEM, and TEMPEST systems (Smith and Annan, 1997; Lane et al., 2000; Smith, Fountain and Allard, 2003).

By the same token, Fugro has been involved in the continuing development of helicopter frequency-domain AEM systems including DIGHEM and RESOLVE. Based upon this combined experience and seeing the need for a broader band, high power helicopter time-domain AEM system, Fugro has introduced the HeliGEOTEM system in 2005. This system brings together the proven GEOTEM/MEGATEM technology with the greater operational flexibility and improved lateral resolution of helicopter mountedAEM systems.

Published in First Break, November, 2005, Volume 23, pages 73-78.
© 2005 European Association of Geoscientists & Engineers. Single copies of the article may be printed - visit First Break online.

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