Northern Ireland, page-8

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The VTEM™ and ZTEM™ helicopter-borne electromagnetic systems are examples of active source (time-domain EM) and passive natural field (tipper AFMAG) systems that were primarily designed for deep penetration mineral exploration applications. Yet, examples of successful VTEM™ and ZTEM™ applications for gold exploration also exist around the world. The VTEM™ system combines near surface high resolution resistivity imaging and deep penetration making it a low cost, “fly-to-drill” direct-detection and mapping tool. The ZTEM™ system uses worldwide sferic thunderstorm activity as its primary EM source field and, like other ground natural source EM methods, such as AMT, is capable of depths of investigation ranging from tens to thousands of meters. Coupling this with its sensitivity to weak lateral resistivity contrasts and the benefits of rapid 2D-3D inversion make it a powerful subsurface rapid reconnaissance geologic mapping tool.