Inductive and Galvanic SAM/HeliSAM
Inductive and Galvanic SAM/HeliSAM
Discovery has exclusive rights to provide cutting edge HeliSAM technology to all of North America through partnering with Australia based, GAP Geophysics.
Inductive HeliSAM – (Helicopter Sub-Audio Magnetics) is a cutting-edge exploration methodology designed for deep EM investigation far beyond the capability of conventional airborne platforms.
Modern Airborne Electromagnetic (AEM) systems have minimal penetration capabilities due primarily to limited transmitter dipole-moment (NIA). The HeliSAM hybrid Ground-Air system combines very large ground based transmitter loops with a lightweight Helicopter towed airborne high sensitivity B-field receiver system. The transmitter configuration provides the same advantages and disadvantages as large loop ground TEM surveys, but coupled with an airborne B-field high sensitivity receiver the HeliSAM system offers many advantages. The methodology is particularly well suited to massive sulphide greenfield exploration in environmentally sensitive regions, topographically rugged terrain, areas pocketed with lakes or swamps, areas of dense bush or projects that require rapid data acquisition due to short field season or otherwise.
Galvanic HeliSAM – Using large dipole sources to map out current channeling through conductive zones, HeliSAM rapidly acquires high resolution MMR/MMC data while still providing traditional TFEM data.
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Large ground loops coupled with high output transmitters, generate a transmitted electromagnetic field infinitely greater than the highest output AEM Systems, transmitting in the range of 2,000,000 NIA. HeliSAM Transmitter loops typically span many kilometers producing a powerful dipole-moment in the range of 40,000,000 to 1,000,000,000 NIA or greater, drastically increasing depth of exploration and signal to noise for superior resolution. A total-field B-field sensor, measures wide-bandwidth secondary response, commonly over a range 40 milliseconds, fly’s as a tow-bird from most types of commercially available helicopters.
The use of large ground-based loops coupled with high-powered transmitters in the 30 to 50kW range enables an effective source field penetration in the order of kilometers over the hundreds of meters characteristic to AEM systems.Further enhancing exploration capabilities is the use of low base frequencies yielding improved detection of late time long wavelength secondary response. Furthermore, low frequency b-field data acquisition results in smaller response from conductive overburden or weaker conductivity in general, providing a better image on high conductive targets indicative of many ore-body types. The use of large ground loops produces a relatively uniform primary field, providing the ability to survey large areas from single loops.
HeliSAM is an ideal geophysical method for regional exploration as up to 18 sq km of surveying can be completed in a single day. We believe this system is a huge step forward for deep, rapid, airborne exploration.
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