GPX Geophysical Exploration Services
Surface Electromagnetic Surveys
 
TEM surveys involve induction of electromagnetic (EM) fields in the sub-surface via a square or rectangular transmitter loop which has no electrical connection with the earth.  In turn, the sub-surface EM fields induce secondary EM fields in a receiver coil and a receiver attached to this coil measures a transient decay which is diagnostic of ground conditions.

Due to the physics of the technique it is inherently better at detecting conductors in resistive environments rather than resistors in conductive environments.  This technique is ideal for the detection and mapping of continuous, sub-surface, electrical conductors such as a massive sulphide orebody.  It is also used for groundwater and environmental studies where the feature to be mapped is more conductive than its host.  Examples of this would include water filled paleochannels or shear zones, saltwater incursion zones or mapping of leaking industrial waste.

Measurements are normally conducted at spacings of 25 to 200 metres.
 

Processing of TEM data
 
Acquisition of in-loop TEM data
 

E-mail : gpx@gpx.com.au