New Applications with the SIROTEM Mark 3 Transient Electromagnetic System

Resistivity sounding by the SIROTEM Mark 3 transient electromagnetic method offers many advantages over the D.C. method of V.E.S. including being much faster and easier to set-up and obtain the readings; having no electrode effects and minimal lateral effects; and the ability to penetrate deeper for a given array size. These advantages are possible through some unique features of the method such as measuring dunng the transmitter off time and in the same place as the transmitter (features not possible with frequency domain EM methods); by cancelling or reducing known sources of noise; and achieving high levels of Signal enhancement by deep stacking and without the need for heavy power sources. These attributes have enabled the SIROTEM to be applied to some new applications in addition to those involving mineral exploration in the fields of engineering and environmental geophysics including the detection of likely areas of ground subsidence, mapping the extent of groundwater contamination by salinity and effluent and monitoring the spread of such contamination plumes.