Photo of the EM<sup>3</sup

Argus Technologies (a Tremaine Company) has developed the EM3 to perform mobile, non-invasive underground surveys. Argus’ EM3 technology is an innovative adaptation of Geonic's conventional hand-held electromagnetic instrumentation. Such instruments have been used successfully in near surface geophysics and soil studies for decades. Our advancements to this base technology include: 1) mobilizing or placing the instrument on wheels; 2) combining three receivers into one instrument for a nested view of subsurface conditions at successive depths; 3) speeding up data acquisition rates; 4) simultaneously tagging incoming data with real time kinematic (RTK) GPS X, Y, and Z coordinates with centimeter-level accuracy; and 5) developing proprietary data collection and processing software. The result is an instrument that records bulk measurements to a maximum depth of 8-10 meters (about 30 feet) and an effective depth of 6 meters (about 20 feet), as it is towed behind an ATV traveling at 5-10 miles per hour.

Typically three to four readings are recorded per meter using a Rough Rider III (Rugged Notebooks, Orange, CA) . Multi31 (Geomar Software Inc., Mississauga, Ontario, Canada), ArcGIS ArcMap 9.2 (ESRI, Redlands, CA), IDL 6.2 (Research Systems Inc., Boulder, Co), and Workbench (HydroGeophysics Group) are used to process and display raw data, generate contour plots, and invert data, respectively.