FTEM Mapping Projects Showcase

Case Study

The ability of the Tempest^® time domain electromagnetic (TEM) system to acquire high quality conductivity data over large areas, reliably, quickly and economically, enables explorers to efficiently identify high priority targets for further exploration. These attributes have seen Tempest^® become a system of choice of government agencies and private companies worldwide for high quality regional mapping programs.

Namibia

The Namibian Geological Survey commissioned a large regional Tempest^® program in northeastern Namibia in 2011. The aims of the program were to determine the thickness of the Kalahari cover in the area, and to map conductive basement geology, and potentially discrete bedrock conductors that would encourage follow-up by private exploration programs.

TEMPEST has become the system of choice of government agencies and private companies worldwide for high quality regional mapping programs.

The conductivity data image at a depth of 40m reveals the conductive Kalahari cover expected in the area, as well as additional surficial detail such as drainage and topographic effects. Lower in the sequence at 240m depth, the conductive cover is no longer visible and reveals the conductive basal unit of a previously unknown sedimentary basin; isolated conductors and structural structures is also imaged.

The Tempest^® survey exceeded it's aims;

• It successfully mapped zones of conductive Kalahari cover, and indicated thickness of the cover to depths of +120m. This de-risks further exploration by;
• Mapping areas with shallow basement that is relatively inexpensive to drill, and
• Mapping areas where the Kalahari cover is very thick, where drilling will be more expensive, and where geochemical/geophysical techniques may have difficulties
• It successfully mapped bedrock geology and discrete bedrock conductors (even given the regional nature of the survey and 4km line spacing). This encourages further exploration by; direct exploration follow-up of bedrock conductors identified, and more detailed EM surveys to follow-up/infill the regional dataset
• In addition the data imaged in detail a large, previously unknown, sedimentary basin at least 300m thick. This opens up the possibility of a new range of deposit styles and commodities to explore for.

Thanks to the Geological Survey of Namibia for permission to publish the results of this survey.