Why choose Sub-Audio Magnetics (SAM)?
SAM is a patented technique that allows for the simultaneous high definition mapping of both the magnetic and electrical properties in the ground - without sacrificing either quality or efficiency.
Standard surveys can require grounded electrodes, levelled sensors and stationary measurements - limiting the terrain that can be covered in a day. Spatial resolution is therefore often sacrificed for survey area coverage rates. The SAM technique bypasses such issues - providing a particularly good value for money survey.
A ground crew can acquire 20 line km of highly sampled magnetic and electrical property data per day, allowing tighter line spacing. This greater target definition will be at a price per hectare no more than that for conventional techniques that only measure one geophysical property.
SAM can be employed for a wide variety of survey types - mainly mineral exploration, explosive ordnance detection and geotechnical mapping. SAM is well suited to overcome the difficulties of highly conductive surface layers - such as with salt lakes.
What is Sub-Audio Magnetics?
A high power transmitter provides a current source in the sub-audio range (0.3 - 30Hz). Using a fast sampling cesium vapour sensor, the total magnetic field is measured continuously in a moving survey with our TM-7 system. Proprietary signal processing extracts the spatial and time domain survey information.
SAM-Magnetometric Conductivity (MMC) mode
In this survey layout, a galvanic loop is used to inject current directly into the ground, which enables SAM to deliver high definition Total Magnetic Intensity and Magnetometric Conductivity data sets.
This type of survey better suits the detection of faults, fractures, and other geology that is detected by seeking resistive anomalies in conductive terrain (see here for a table comparing geology to survey types).
For larger surveys, it becomes more efficient to go airborne. Our towed-bird configuration uses a light-weight helicopter and our compact easily fitted TM-7 receiver system. The HeliSAM platform has a long track record of success at large scale projects. Read here for more information.
SAM-Fixed Loop Electromagnetics (FLEM) mode
In fixed loop mode, a high powered transmitter will send current through a closed loop, inducing a secondary field in the ground. SAM-FLEM delivers Total Magnetic Intensity, Total Field Electromagnetics and derived 3-component Electromagnetic data from one survey.
This technique is able to detect large conductors (such as massive sulphides) under far greater depth of cover than possible with conventional EM methods.
SAM surveys can be performed in ultra-high precision layouts, to get sub-metre discretisation of phenomena. This is required in the case of explosive ordnance detection, where ubiquitous extra-high definition coverage of an area is needed.
SAM uses the TM7 receiver system, which includes a total-field fast-sampling cesium vapour sensor. Depending on loop size, we will likely utilise one of our proprietary high power transmitter systems. Because the receiver system is lightweight and compact, it has no difficulty being utilised with most helicopter types - allowing for a light-weight aircraft to be used, such as a JetRanger or Robinson R22 or R44.
Our engineering team has produced a suite of in-house properitary data processing solutions and survey planning software. In the interest of industry safety, some of our planning tools are available to our clients.
SAM has been the primary discovery technology for many significant finds. Various reports on successes are available (below) and many recent news articles have been demonstrating the capabilities of the technique. Please contact us for any further information.