MEGWA: Mapping alteration and delineating ore shoots with Hyperspectral Core Imaging at the Sunrise Dam Gold Deposit

Australian Institute of Geoscientists > Events > gold, hyperspectral logging, Sunrise Dam > MEGWA: Mapping alteration and delineating ore shoots with Hyperspectral Core Imaging at the Sunrise Dam Gold Deposit

MEGWA: Mapping alteration and delineating ore shoots with Hyperspectral Core Imaging at the Sunrise Dam Gold Deposit


MEGWA talk for August, presented by Andrew Jenkins, AngloGold Ashanti.

Hyperspectral Core Imaging (HCI) is a relatively new technique that utilises technology traditionally used to map geology from airborne or satellite based platforms, such as Hymap and ASTER respectively. Spectrometers spanning the visible and near-infrared (VNIR) and short-wavelength infrared (SWIR) parts of the electromagnetic spectrum scan the drill core to create a complete raster image with millimetre sized pixels, each equivalent to a TerraSpec reading. This generates approximately 45,000 spectra per metre allowing the mineralogy to be measured in high detail and providing spatial context to the mineralogy.

This presentation will briefly introduce the HCI technology and then describe how the huge dataset was converted into a set of simple useful products beneficial to a working mine. The case study site will be the world-class Sunrise Dam Gold Mine, a classic orogenic gold system and one of the world’s best from our very own Yilgarn Craton. The very coarse-grained nuggetty nature of the gold at Sunrise Dam makes delineating the ore zones challenging. Around the mineralised structures, alteration is both more consistent than the gold geochemistry and delivers a broader spatial footprint to detect. HCI enabled for the rapid and objective measurement of the alteration and the resultant data was used to create a 3D model of the fluid conduit network that our gold–bearing fluids exploited.