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Event Address
Geoscience Australia, Cnr Jerrabomberra Ave & Hindmarsh Dr Symonston
Event Start
16:30
Event End
1900
Event Details
Abstract:
A portable, broadband TEM system, Loupe, has been developed for the purpose of measuring the distribution of near-surface electrical conductivity. The system records continuously using a three-component coil receiver mounted on an ergonomic backpack from signals generated from a small (660mm) diameter transmitter loop mounted on a similar backpack.
The Loupe system is designed to measure primarily in the top 25 metres of the ground, previously the charter of frequency-domain EM systems. Using modern electronics and software we have been able to overcome many of the problems associated with the broad bandwidth needed to define near surface conductivity with a time domain system. Sampling at around 500,000 samples per second and processed to produce a measurement of secondary field every second, the Loupe system provides very high spatial resolution. Data can be viewed as the operators walk, allowing survey redesign as necessary.
During 2019, trial surveys have been conducted with Loupe in a number of near-surface applications including mineral exploration on surface and underground, geological / regolith mapping, study of groundwater around tailings storage facilities and the mapping of structural features in open-cut mines. We see a wide application for Loupe in mapping seepage both from mine tailings and acid mine drainage.
The Loupe system has proved to be extremely versatile working in difficult terrain and areas with high electromagnetic interference such as mine sites and urban sites. Special challenges are presented when working underground due to power reticulation, vehicle movement, infrastructure and particularly steel mesh reinforcing. We will give examples showing data collected in these challenging circumstances.
During this presentation, we will summarise the Loupe system and show results from several recent surveys.
Greg is the director of Loupe Geophysics based in WA. He has been working with geophysical systems in mining, groundwater and environmental applications for over 40 years