September 16, 2009
VTEM detects the Night Hawk Lake conductor from 705 m above.
Read the case study (PDF)
March 24, 2009
BENTON RESOURCES, ROYAL ROADS & GOLDEN DORY APPROVE 2009 PROGRAM FOR LONG RANGE NICKEL JOINT VENTURE, NEWFOUNDLAND – DRILL TARGETS IDENTIFIED
"... Among the targets selected for further work is a 600 metre long VTEM conductive anomaly described by Geotech Ltd. as “a relatively strong conductor consistent with massive sulphides”. This target has been selected for testing by diamond drilling, and it is anticipated that additional targets will be developed from results of the prospecting and ground geophysical surveys."
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VTEM | Airborne Gravity | AFMAG | Hummingbird | Hawk
AFMAG - Audio-Frequency Magnetics
Passive electromagnetic system
Features:
- Very deep investigation.
- Multi-frequency geophysical information.
- Resolution in wide-range of conductivity.
- Lower cost equipment and surveys.
- Surveys may be flown at 200 meters altitude.
Description:
Unlike other electromagnetic methods the AFMAG utilizes natural alternating magnetic fields in the audio-frequency range. This has advantages over active airborne EM systems using dipole artificial field sources. Such artificial fields decay inversely proportional to the cube of the distance from its source. Responses from deep conductive targets can be very low and masked by noise and anomalies of small but shallow geologic bodies.
The natural magnetic field used in the AFMAG technology is primarily homogeneous and its penetration depth depends on rock resistivity only. A deep conductor in highly resistive surroundings can be better detected by AFMAG.
Another advantage of the AFMAG is good resolution for relatively resistive objects. It makes this method very useful not only for detecting conductors but also for general geological mapping and exploration of poorly conductive objects such as Kimberlite pipes.
This new technology has now been proven over known test sites. These flights were conducted with a helicopter-borne AFMAG device and processed using advanced digital technologies and signal processing algorithms.
| Specifications: | |
|---|---|
| Lowest frequency | 30 Hz |
| Highest frequency | 6000 Hz |
| Number of frequencies | 7 |
| Maximum sample rate | 5 sps |
| System weight | 90 Kg |
AFMAG DATA COMPARISON REID-MAHAFFY TEST SITE
Click an image to enlarge it.
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GEOTECH TIME-DOMAIN (LINE #20)
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ELFMAG IP (LINE #20; ALTITUDE 100 METER)
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ELFMAG IP (LINE #20; ALTITUDE 400 METER)