Extracting more from exploration soil samples. The evolution of UltraFine+ and next generation analytics

Noble, Ryan R.P.1, Cole, David T.1, Williams, Morgan J.1, Lau, Ian C.1, Anand, Ravi R.1

1CSIRO Mineral Resources, Kensington, Perth, Western Australia

Continued exploration success requires consistent innovation. While large geochemical surveys conducted by mining companies are common, the suite of data we collect beyond standard soil chemistry has remained stagnant. A novel integration of analytical  methods known as UltraFine+™ extracts the “standard soil chemistry” of the <2 µm soil clay fraction, which is combined with soil VIS-NIR and FTIR spectral mineralogy proxies and physicochemical properties to improve interpretation of soil chemistry leading to better targeting for gold and base-metal exploration.

At numerous study sites across Australia, we demonstrate how the integration of spectral mineralogy proxies and particle-size variation can assist in understanding landscape processes and anomaly formation, and in some settings provide explanations for false positives. Through providing uncertainty estimates on spatial geochemical predictions and reducing the influence of explainable false positives, key information is communicated to decision makers for more confident targeting. A marked decrease in censored results using UltraFine+TM for gold (from 63% to 10% below detection limit) is a major improvement over historical techniques. Automated analytics pipelines using a variety of unsupervised machine learning techniques (e.g. dimensionality reduction, clustering) ensure the rapid interpretation of survey datasets, and accelerate the path to discovery.


Ryan is a principal research scientist with CSIRO working in soil and groundwater chemistry applied to mineral exploration

About the GSA

The Geological Society of Australia was established as a non-profit organisation in 1952 to promote, advance and support Earth sciences in Australia.

As a broadly based professional society that aims to represent all Earth Science disciplines, the GSA attracts a wide diversity of members working in a similarly broad range of industries.