The Use of Airborne Gamma Ray Spectrometry by M.I.M. Exploration—A Case Study From the Mount Isa Inlier, North West Queensland, Australia
Jayawardhana, P.M.,and Sheard, S.N.
1. M.I.M. Exploration Pty. Ltd.
This paper describes how airborne radiometrics has been used by M.I.M. Exploration Pty. Ltd. (MIMEX) to aid mineral exploration. The case study for this paper focuses on the Mount Isa airborne survey undertaken from 1990–92. During this survey both radiometrics and magnetics were recorded over 639 170 line kilometres. Due to the perceived value of the radiometric data, stringent calibration procedures, including the creation of a test range, were adopted. In addition to the newly flown areas, agreements were entered into to acquire existing data (76 760 line kilometres) from other companies. These were reprocessed and stitched in to give an overall ‘seamless join’ to images. The total area covered by the Mount Isa airborne survey was 1 513 000 km 2. Over the last five years MIMEX has undertaken a number of projects and generated a number of products to maximise the in-house use of radiometrics for mineral exploration. This paper highlights these products, techniques, and results based on radiometric signatures of major mines in the Mount Isa Inlier; radioelement contour maps; geomagnetic/radiometric interpretation maps; lithological mapping; regolith mapping; geochemical sampling; and spatial modelling using geographical information systems (GIS). Due to the recent introduction of GIS technology and better techniques for handling MIMEX’s high quality digital data, there has been a revived interest in making more use of image data sets. The integration of raster and vector data sets for both spectral and spatial modelling has highlighted the vast potential that lies ahead.