Airborne Geophysical Surveys

AIRBORNE MAGNETIC GRADIOMETER & VLF-EM SYSTEM

For precious metal exploration & geologic mapping

 The CMG airborne magnetic gradiometer and VLF System is based on the Potassium sensors, which provide the highest sensitivity available in the industry. CMG uses the large volume (75 mm) sensors that are specifically designed for low-gradient applications such as exploration for Gold, Silver, Platinum, Palladium, Uranium, porphyry Copper deposits and mapping weakly magnetic geologic structures that may have concentrated precious metal deposits. 

The VLF-EM system is a two frequency multi-component receiver that measures the in-phase and quadrature-phase fields from two separate radio transmitters in the frequency range from 17 kHz to 24 kHz. Such measurements can identify very weakly conductive structures that may have acted as pathways for metal-rich fluids which can be concentrated into economic mineral deposits containing precious metals in sulphide.

MAGNETIC GRADIOMETER SENSORS

§  Three high sensitivity potassium total magnetic field sensors

§  Spacing is 3.2 m

§  High sensitivity to +/- 0.001 nT

§  Absolute accuracy is better than 0.1 nT

§  Sensor heading error is 0.05 nT or less on all axes

§  Gradient tolerance > 15,000 nT

§  Range is 10,000 nT to 125,000 nT

§  Vertical and cross-line gradients are measured directly

§  In-line gradient is calculated 

VLF-EM SENSORS 

§  Two frequencies (roughly orthogonal transmitter stations)

§  Two component measurement (in-phase and quadrature-phase)

§  Total field is computed as vector sum of both frequency (quadrature only)

§  In-phase may be extracted under certain conditions 

ADDITIONAL & OPTIONAL SENSORS 

§  Five crystal radiometrics package measuring K, Th, and U windows

§  GPS with differential real time correction

§  On-board navigation to ensure accurate line spacing

§  Radar altimeter (allows for Digital Elevation Model)

§  All data is digitally recorded at 10 to 20 Hz sample rate

ADVANTAGES AND DIFFERENCE FROM OTHER SYSTEMS:

The main difference between our system and Aeroquest and Geotech is that we use either natural fields (AfMag) or plane wave EM fields (VLF) while AQL and Geotech use a large transmitter dipole. Natural fields and plane wave methods are better at energizing and detecting weakly conductive targets such as gold and silver in low sulphide concentrations or porphyry copper deposits or mapping geologic structures.

Our system operates at 40-50% less cost than AeroTEM or VTEM so it is much cheaper.