Streaming SA – The Story - (Past, Present & Future)

Summary

Compilation of the first South Australian state radiometric image was commenced almost a decade ago. Vastly differing vintage and quality of data between surveys provided a significant problem with the levelling of surveys to one datum. A back calibration method was adopted to derive the true ground concentrations of the three radio-elements, U, TH and K.

The significant time required to back-calibrate one survey via ground-based points was a major obstacle, therefore, a vehicular mounted system has been developed that incorporates a constant streaming back calibration method. Airborne datasets that have been levelled using this method have been subsequently merged to create a suite of much improved State radiometric images.

The Australia Wide Airborne Geophysical Survey (AWAGS2), recently completed by Geoscience Australia (GA) consisted of a number of magnetic and radiometric tie-lines flown over the Australian continent, and around the coast. Constant streaming has been used to collect ground data coincident with the AWAGS2 lines. A comparison between the ground data and the AWAGS2 data back calibrated to ground level, exhibits good consistency, thereby validating the use of constant streaming for back calibration. Numerous other acquisition tests aimed at assessing quality and consistency have been completed, including a direct comparison with airborne data, a ground based grid, dose rate monitoring at Radium Hill, and several dirt versus bitumen and acquisition speed tests.

Future applications will tend towards regional and detailed surveys as an aid to mapping of project areas.

Key words::

• Portable Spectrometer
• radiometric mapping
• Vehicle-borne acquisition
• airborne survey levelling
• back calibration